Latrobe,LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A)

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: Latrobe LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A) Product Information -:- For detailed product information, please contact sales. -: Latrobe LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A) Synonyms -:- For detailed product information, please contact sales. -:

Latrobe LSS™ 135M Nitriding Steel (ASTM A355 Class A) Product Information -:- For detailed product information, please contact sales. -: # **PRODUCT DATASHEET: LATROBE LSS™ 135M NITRIDING STEEL (ASTM A355 CLASS A)** ## **EXECUTIVE SUMMARY** Latrobe LSS™ **135M Nitriding Steel** is a premium-grade **aluminum-chromium-molybdenum alloy steel** specifically engineered for **gas nitriding applications** requiring exceptional surface hardness, wear resistance, and dimensional stability. Conforming to **ASTM A355 Class A specifications**, this specialized steel contains **approximately 1.0% aluminum** which forms extremely hard aluminum nitride compounds during the nitriding process, achieving surface hardness up to **72 HRC** with excellent case depth control. Designed for components subjected to **severe wear, fatigue loading, and moderate impact conditions**, 135M offers an optimal balance of **core toughness, high surface hardness, and minimal distortion** during heat treatment. This advanced nitriding steel is characterized by its **superior response to nitriding treatments, good machinability in the annealed state, and excellent retention of core properties** after case hardening. Latrobe's enhanced manufacturing processes ensure **exceptional cleanliness, precise chemistry control, and uniform microstructure** – critical factors for consistent nitriding performance and extended component service life in demanding applications. --- ## **METALLURGICAL DESIGN** ### **Nitriding-Specific Engineering** 135M employs a specialized alloying system optimized for nitriding response: 1. **Aluminum Nitride Formation:** 0.85-1.20% aluminum promotes formation of extremely hard, finely dispersed AlN precipitates during nitriding 2. **Chromium Enhancement:** 1.40-1.80% chromium contributes to additional nitride formation and improved core hardenability 3. **Molybdenum Stabilization:** 0.20-0.30% molybdenum prevents temper embrittlement and enhances high-temperature stability 4. **Carbon Optimization:** 0.35-0.45% carbon provides adequate core strength without compromising nitriding kinetics ### **Nitriding Mechanism Advantages** - **Rapid Nitrogen Absorption:** Aluminum acts as a strong nitride-forming element, accelerating case development - **Hard Nitride Precipitation:** AlN and CrN precipitates create exceptionally high surface hardness (68-72 HRC) - **Gradual Case-to-Core Transition:** Controlled diffusion produces smooth hardness gradients - **Minimal Distortion:** Low processing temperatures (925-1050°F/496-566°C) maintain dimensional stability ### **Latrobe Manufacturing Advantages** - **Precise Aluminum Control:** Critical for consistent nitride formation and case properties - **Enhanced Cleanliness:** Low inclusion counts for improved fatigue performance - **Uniform Microstructure:** Controlled processing ensures predictable nitriding response - **Stress Management:** Optimized annealing for minimal machining distortion --- ## **CHEMICAL COMPOSITION** ### **Standard Composition Ranges (Weight %)** | Element | Minimum | Maximum | Typical | Metallurgical Function in Nitriding | |---------|---------|---------|---------|-------------------------------------| | **Carbon (C)** | 0.35 | 0.45 | 0.40 | Core strength, hardenability | | **Manganese (Mn)** | 0.40 | 0.70 | 0.55 | Hardenability, deoxidation | | **Phosphorus (P)** | — | 0.025 | 0.015 | Residual (controlled) | | **Sulfur (S)** | — | 0.025 | 0.015 | Residual (controlled) | | **Silicon (Si)** | 0.20 | 0.45 | 0.30 | Deoxidation, strength | | **Chromium (Cr)** | 1.40 | 1.80 | 1.60 | Nitride formation, hardenability, corrosion resistance | | **Molybdenum (Mo)** | 0.20 | 0.30 | 0.25 | Temper embrittlement resistance, nitride stability | | **Aluminum (Al)** | 0.85 | 1.20 | 1.00 | Primary nitride-forming element | | **Nickel (Ni)** | — | 0.25 | 0.15 | Optional for enhanced toughness | ### **Critical Element Control for Nitriding** - **Aluminum Precision:** ±0.05% control for consistent nitride formation - **Nitrogen Affinity Balance:** Optimized Al/Cr ratio for controlled case development - **Tramp Element Control:** Low Sn, Sb, As to prevent temper embrittlement - **Gas Content:** Oxygen <25 ppm, Hydrogen <2 ppm for clean steel ### **Latrobe Premium Modifications** - **Enhanced Purity:** Extra-low sulfur and phosphorus (S<0.010%, P<0.015%) - **Micro-Alloying:** Controlled titanium (0.01-0.03%) for grain refinement - **Calcium Treatment:** Optional for improved sulfide shape control - **Boron Addition:** Optional (0.001-0.003%) for enhanced core hardenability ### **Comparison with Other Nitriding Steels** | Element | 135M (A355-A) | Nitralloy 135 | 41xx Series | Advantage | |---------|---------------|---------------|-------------|-----------| | **Aluminum** | 0.85-1.20% | 0.95-1.30% | None | Superior nitride hardness | | **Chromium** | 1.40-1.80% | 1.40-1.80% | 0.80-1.10% | Enhanced case depth | | **Molybdenum** | 0.20-0.30% | 0.15-0.25% | 0.15-0.25% | Better temper resistance | | **Response** | Excellent | Excellent | Good | More consistent | --- ## **PHYSICAL PROPERTIES** ### **Basic Physical Constants** | Property | Value | Units | Test Standard | |----------|-------|--------|----------------| | **Density** | 0.283 | lb/in³ (7.83 g/cm³) | ASTM B311 | | **Melting Range** | 2650-2750 | °F (1454-1510°C) | | | **Modulus of Elasticity** | 29.5 × 10⁶ | psi (203 GPa) | ASTM E111 | | **Shear Modulus** | 11.5 × 10⁶ | psi (79 GPa) | ASTM E143 | | **Poisson's Ratio** | 0.29 | | ASTM E132 | | **Thermal Conductivity** | 21.0 | BTU·in/(hr·ft²·°F) @ 212°F | ASTM E1225 | | **Specific Heat** | 0.11 | BTU/(lb·°F) @ 68-212°F | ASTM E1269 | | **Coefficient of Thermal Expansion** | 6.4 × 10⁻⁶ | /°F (20-200°C) | ASTM E228 | | **Electrical Resistivity** | 44 | μΩ·cm | ASTM B193 | | **Magnetic Permeability** | Ferromagnetic | | All conditions | ### **Thermal Properties Relevant to Nitriding** | Temperature | Thermal Conductivity | Specific Heat | Thermal Diffusivity | |-------------|----------------------|---------------|---------------------| | **Nitriding Temp (975°F/524°C)** | 22.5 BTU·in/(hr·ft²·°F) | 0.14 BTU/(lb·°F) | 0.075 in²/s | | **Tempering Range (1100°F/593°C)** | 23.0 BTU·in/(hr·ft²·°F) | 0.15 BTU/(lb·°F) | 0.078 in²/s | | **Austenitizing (1600°F/871°C)** | 24.5 BTU·in/(hr·ft²·°F) | 0.16 BTU/(lb·°F) | 0.085 in²/s | ### **Nitriding-Specific Physical Properties** - **Nitrogen Diffusion Coefficient:** 1.2-1.8 × 10⁻⁷ cm²/s @ 975°F (524°C) - **Case Growth Rate:** 0.010-0.015 in/day (0.25-0.38 mm/day) typical - **Thermal Expansion Match:** Excellent case-to-core compatibility minimizes stress - **Distortion Factor:** <0.001 in/in typical during nitriding --- ## **MECHANICAL PROPERTIES** ### **Core Properties (Before Nitriding)** #### **Quenched and Tempered Core (Typical)** *Hardening: 1600-1650°F (871-899°C) oil quench, Temper: 1100-1200°F (593-649°C)* | Property | Value | Units | |----------|-------|--------| | **Hardness** | 28-32 | HRC | | **Tensile Strength** | 130-150 | ksi (895-1035 MPa) | | **Yield Strength (0.2%)** | 115-135 | ksi (795-930 MPa) | | **Elongation (2")** | 14-18 | % | | **Reduction of Area** | 45-55 | % | | **Charpy V-Notch Impact** | 40-60 | ft-lb @ 68°F | #### **Annealed Condition (For Machining)** | Property | Value | Units | |----------|-------|--------| | **Hardness** | 187-229 | HB (89-99 HRB) | | **Tensile Strength** | 85-105 | ksi (585-725 MPa) | | **Yield Strength** | 55-75 | ksi (380-515 MPa) | | **Machinability Rating** | 55-65 | % of 1212 steel | ### **Nitrided Case Properties** #### **Gas Nitrided (48-72 hours @ 975°F/524°C)** | Property | Case Surface | Case Depth 0.010" | Case Depth 0.020" | Case-to-Core Transition | |----------|--------------|-------------------|-------------------|-------------------------| | **Hardness** | 68-72 HRC | 65-69 HRC | 60-64 HRC | 50-55 HRC | | **Case Depth (Effective)** | 0.015-0.025" | 0.38-0.64 mm | | | | **Total Case Depth** | 0.025-0.040" | 0.64-1.02 mm | | | | **White Layer Thickness** | 0.0002-0.0008" | 5-20 μm | Controlled | | | **Surface Residual Stress** | -80 to -120 | ksi (Compressive) | | | ### **Fatigue Properties (Nitrided)** | Condition | Endurance Limit (10⁷ cycles) | Fatigue Improvement | Fatigue Ratio | |-----------|----------------------------|---------------------|---------------| | **Unnotched, Rotating Bending** | 85-95 ksi | +40-50% vs. unnitrided | 0.65-0.70 | | **Notched (Kt=3), Rotating Bending** | 55-65 ksi | +60-80% vs. unnitrided | | | **Contact Fatigue (Hertzian)** | 250-300 ksi | Excellent pitting resistance | | | **Corrosion Fatigue** | 45-55 ksi (3.5% NaCl) | Good retention | | ### **Wear Properties** | Wear Mechanism | Nitrided 135M | Unnitrided 135M | Improvement Factor | |----------------|---------------|-----------------|---------------------| | **Abrasive Wear** | Excellent | Good | 8-12× | | **Adhesive Wear** | Excellent | Fair | 10-15× | | **Erosive Wear** | Very Good | Fair | 6-10× | | **Fretting Wear** | Excellent | Poor | 15-20× | ### **Hardenability Data (Jominy Test)** | Distance from Quenched End | Hardness (HRC) | |----------------------------|----------------| | **1/16" (1.6 mm)** | 52-56 | | **1/8" (3.2 mm)** | 50-54 | | **1/4" (6.4 mm)** | 48-52 | | **1/2" (12.7 mm)** | 44-48 | | **1" (25.4 mm)** | 36-40 | | **2" (50.8 mm)** | 28-32 | **Note:** Through-hardenable to approximately 2 inches (50 mm) diameter in oil quench ### **Elevated Temperature Properties** | Temperature | Core Hardness Retention | Nitrided Case Hardness | |-------------|-------------------------|-------------------------| | **Room Temperature** | 100% | 68-72 HRC | | **600°F (316°C)** | 90-94% | 65-69 HRC | | **800°F (427°C)** | 80-85% | 60-64 HRC | | **1000°F (538°C)** | 65-70% | 55-59 HRC | | **Maximum Service** | 900°F (482°C) | 1000°F (538°C) short term | --- ## **NITRIDING PERFORMANCE** ### **Gas Nitriding Response** #### **Standard Gas Nitriding Cycle** - **Temperature:** 925-1050°F (496-566°C) - **Time:** 24-96 hours (typically 48-72 hours) - **Atmosphere:** Ammonia (NH₃) with 15-35% dissociation - **Cooling:** Slow cool in nitrogen or furnace cool - **Case Depth:** 0.015-0.040" (0.38-1.02 mm) achievable #### **Case Depth Development** | Nitriding Time | Case Depth (Effective) | Total Case Depth | White Layer | |----------------|------------------------|------------------|-------------| | **24 hours** | 0.010-0.015" | 0.015-0.020" | 0.0002-0.0005" | | **48 hours** | 0.015-0.020" | 0.020-0.030" | 0.0003-0.0006" | | **72 hours** | 0.020-0.025" | 0.025-0.035" | 0.0004-0.0008" | | **96 hours** | 0.025-0.030" | 0.030-0.040" | 0.0005-0.0010" | ### **Plasma (Ion) Nitriding** - **Temperature:** 850-1050°F (454-566°C) - **Time:** Typically 20-40% less than gas nitriding - **Advantages:** Better control, reduced white layer, lower distortion - **Case Depth:** Similar to gas nitriding with proper parameters - **Hardness:** 70-73 HRC achievable ### **Salt Bath Nitriding** - **Temperature:** 1050-1100°F (566-593°C) - **Time:** 1-4 hours typical - **Case Depth:** 0.002-0.008" (0.05-0.20 mm) - **Applications:** Where thin, hard cases are sufficient ### **Nitriding Process Comparison** | Process | Hardness (HRC) | Case Depth | Distortion | White Layer Control | |---------|----------------|------------|------------|---------------------| | **Gas Nitriding** | 68-72 | Deepest | Moderate | Fair | | **Plasma Nitriding** | 70-73 | Deep | Low | Excellent | | **Salt Bath** | 65-70 | Shallow | Very Low | Good | | **Ferritic Nitrocarburizing** | 55-60 | Very Shallow | Minimal | Excellent | ### **Post-Nitriding Treatments** - **White Layer Removal:** Light polishing or honing if required - **Oxidation:** Steam or post-oxidation for corrosion resistance - **Stress Relief:** Low-temperature treatment if needed - **Finishing:** Final grinding or lapping to size --- ## **MACHINABILITY** ### **Machining in Annealed Condition** #### **General Guidelines** - **Hardness:** 187-229 HB (89-99 HRB) - **Machinability Rating:** 55-65% of 1212 steel - **Chip Formation:** Stringy chips - good chipbreakers required - **Surface Finish:** Good with proper technique #### **Recommended Cutting Parameters** | Operation | Speed (SFM) | Feed | Depth of Cut | Tool Material | |-----------|-------------|------|--------------|---------------| | **Turning** | 180-220 | 0.010-0.018 IPR | 0.100-0.200" | C2/C3 Carbide | | **Milling** | 130-170 | 0.004-0.007 IPT | 0.080-0.150" | HSS or Carbide | | **Drilling** | 70-100 | 0.005-0.008 IPR | Full diameter | HSS Drills | | **Tapping** | 30-50 | — | — | HSS Taps, good lubricant | | **Broaching** | 15-25 FPM | 0.002-0.004 IPT | — | HSS Broaches | ### **Machining After Heat Treatment (Pre-Nitriding)** - **Hardness:** 28-32 HRC after quenching and tempering - **Machinability:** Fair - requires carbide tooling - **Finishing:** Grinding often required for final dimensions - **Considerations:** All machining should be completed before nitriding ### **Grinding After Nitriding** - **Extreme Difficulty:** Not recommended due to extreme hardness - **Alternative Methods:** Honing, lapping, or EDM if absolutely necessary - **Pre-Nitriding Finish:** Critical - achieve final dimensions before nitriding - **Allowances:** Typically 0.0005-0.0015" for growth during nitriding ### **Electrical Discharge Machining (EDM)** - **Suitable:** For making changes after nitriding if absolutely necessary - **Recast Layer:** Must be removed by subsequent processing - **Stress Effects:** May affect nitrided case properties - **Recommendation:** Avoid if possible; make all features before nitriding --- ## **HEAT TREATMENT** ### **Pre-Nitriding Heat Treatment** #### **Hardening Cycle** 1. **Preheat:** 1200-1250°F (649-677°C) 2. **Austenitize:** 1600-1650°F (871-899°C) 3. **Soak Time:** 30 minutes per inch at temperature 4. **Quenching:** Oil quench to below 150°F (66°C) 5. **Immediate Tempering:** Begin within 1 hour #### **Tempering** - **Temperature:** 1100-1200°F (593-649°C) for nitriding applications - **Time:** 2-4 hours per inch, minimum 2 hours - **Double Temper:** Recommended for dimensional stability - **Resultant Hardness:** 28-32 HRC ideal for nitriding ### **Stress Relieving** - **Before Final Machining:** 1100-1150°F (593-621°C) for 1-2 hours - **After Rough Machining:** 1050-1100°F (566-593°C) for 1-2 hours - **Purpose:** Minimize distortion during nitriding ### **Special Considerations for Nitriding Preparation** - **Surface Preparation:** Clean, oil-free surfaces essential - **Masking:** Areas to remain soft can be masked with tin or copper plating - **Fixturing:** Proper support to minimize distortion - **Temperature Uniformity:** Critical for consistent case depth ### **Post-Nitriding Treatments** - **Stress Relief:** 300-400°F (149-204°C) if required - **Oxidation:** 600-700°F (316-371°C) in steam for corrosion resistance - **Cooling:** Controlled cooling to minimize distortion --- ## **INTERNATIONAL STANDARDS & SPECIFICATIONS** ### **Primary Material Standards** | Standard | Designation | Title / Description | |----------|-------------|---------------------| | **ASTM A355** | Class A | Standard Specification for Steel Bars, Alloy, for Nitriding | | **AMS** | 6470 | Steel Bars, Forging, and Tubing, Nitriding Grade | | **SAE** | 135M | Nitralloy 135 Modified | | **UNS** | K24065 | Unified Numbering System | | **DIN** | 1.8550 | 34CrAlMo5 | | **EN** | 1.8550 | 34CrAlMo5 | | **ISO** | 34CrAlMo5 | International Standard | | **JIS** | SACM645 | Japanese Industrial Standard | | **GB** | 38CrMoAlA | Chinese Standard | ### **Nitriding Process Standards** - **AMS 2759/10:** Gas Nitriding of Steel Parts - **AMS 2759/11:** Plasma (Ion) Nitriding of Steel Parts - **AMS 2759/12:** Salt Bath Nitriding of Steel Parts - **ISO 9001:** Quality Management Systems - **NADCAC AC7108:** Special Processes - Heat Treating ### **Testing Standards for Nitrided Parts** - **ASTM E384:** Microindentation Hardness Testing (Case depth measurement) - **ASTM E92:** Vickers Hardness Testing - **ASTM E18:** Rockwell Hardness Testing - **ASTM E112:** Grain Size Determination - **ASTM E3:** Preparation of Metallographic Specimens ### **Industry-Specific Specifications** - **Aerospace:** Customer-specific requirements from Boeing, Airbus, etc. - **Automotive:** OEM specifications for transmission and engine components - **Tool & Die:** Industry standards for nitrided tooling - **Military:** MIL-S specifications for specialized applications --- ## **APPLICATIONS** ### **Aerospace Industry** - **Engine Components:** Turbine shafts, compressor blades, gearbox components - **Actuation Systems:** Actuator screws, ballscrews, worm gears - **Landing Gear:** Bushings, pins, wear surfaces - **Flight Controls:** Hinge points, bearing surfaces, actuator components ### **Automotive & Transportation** - **Transmission Parts:** Gears, synchronizers, shift forks, clutch components - **Engine Components:** Camshafts, crankshafts, rocker arms, valve train parts - **Fuel Injection:** Plungers, barrels, distributor rotors - **Steering Systems:** Rack and pinion gears, steering column components ### **Industrial Machinery** - **Gears & Gearboxes:** High-wear gears, pinions, splined shafts - **Hydraulic Components:** Pump pistons, cylinder rods, valve spools - **Machine Tools:** Lead screws, ways, spindle components - **Textile Machinery:** Guides, rollers, cams, wear plates ### **Tool & Die Applications** - **Plastic Molds:** Core pins, ejector pins, mold inserts - **Die Casting:** Cores, inserts, ejector pins - **Stamping Dies:** Wear plates, guide posts, punch holders - **Extrusion Tools:** Dies, mandrels, wear components ### **Oil & Gas Industry** - **Downhole Tools:** Valve components, wear sleeves, tool joints - **Pump Components:** Plungers, liners, valve seats - **Valve Trims:** Gates, seats, stems for severe service - **Drilling Equipment:** Wear rings, bushings, bearing surfaces ### **Other Specialized Applications** - **Medical Devices:** Surgical instrument components, implant tooling - **Food Processing:** Wear parts for processing equipment - **Printing Industry:** Rolls, cylinders, bearing surfaces - **Marine Applications:** Shafting, bearing surfaces, valve components ### **Application-Specific Recommendations** | Application Type | Core Hardness | Case Depth | Nitriding Process | Key Requirements | |-----------------|---------------|------------|-------------------|------------------| | **Gears** | 30-34 HRC | 0.020-0.030" | Gas or Plasma | Wear resistance, pitting resistance | | **Hydraulic Rods** | 28-32 HRC | 0.015-0.025" | Gas or Plasma | Wear, corrosion resistance | | **Injection Molding** | 28-32 HRC | 0.010-0.020" | Plasma Preferred | Wear, corrosion, release | | **Aerospace Actuators** | 30-34 HRC | 0.015-0.025" | Plasma | Precision, wear, fatigue | | **Tooling Components** | 32-36 HRC | 0.008-0.015" | Salt Bath or Plasma | Wear, minimal distortion | --- ## **WELDING & REPAIR** ### **Weldability Characteristics** - **Carbon Equivalent (CE):** Approximately 0.75-0.85 - **Weldability Rating:** Poor - not recommended for general fabrication - **Primary Concern:** Aluminum content promotes hot cracking - **Repair Welding:** Possible with specialized procedures for salvage operations ### **If Welding is Absolutely Necessary** #### **Pre-Welding Requirements** - **Preheat:** 600-800°F (316-427°C) minimum - **Filler Metal:** Nickel-base alloys (ENiCrFe-2, ENiCrMo-3) recommended - **Joint Design:** Generous radii, avoid restraint - **Cleaning:** Absolute cleanliness required #### **Welding Procedures** 1. **Remove Nitrided Case:** Grind away nitrided layer completely 2. **Preheat Uniformly:** To specified temperature 3. **Welding Process:** GTAW (TIG) preferred for control 4. **Post-Weld Heat Treatment:** Full reheat treatment required 5. **Re-nitriding:** Necessary to restore surface properties ### **Alternative Joining Methods** - **Mechanical Fastening:** Preferred joining method - **Adhesive Bonding:** Suitable for some applications - **Brazing:** Possible with proper techniques - **Diffusion Bonding:** For specialized applications ### **Repair Considerations** - **Economic Viability:** Often more cost-effective to replace than repair - **Property Restoration:** Difficult to match original properties - **Distortion Risk:** High during repair welding - **Recommendation:** Consult with Latrobe technical services before attempting repairs --- ## **CORROSION RESISTANCE** ### **Nitrided Surface Behavior** - **General Corrosion:** Similar to unnitrided steel in most environments - **Atmospheric Corrosion:** Moderate improvement due to surface compound layer - **Galvanic Corrosion:** Can occur when coupled with dissimilar metals - **Chemical Resistance:** Good resistance to many chemicals and solvents ### **Enhanced Corrosion Protection** - **Post-Nitriding Oxidation:** Steam treatment creates Fe₃O₄ layer for improved corrosion resistance - **Plating:** Chrome or nickel plating over nitrided surface for maximum protection - **Coatings:** Paints and polymers can be applied over nitrided surfaces - **Passivation:** Chemical treatments to enhance natural oxide layer ### **Environmental Limitations** - **Acidic Environments:** Poor resistance to strong acids - **Alkaline Solutions:** Good resistance to mild alkalis - **Marine Environments:** Requires additional protection for long-term service - **High Temperature Oxidation:** Limited to 1000°F (538°C) maximum --- ## **QUALITY ASSURANCE** ### **Material Testing** - **Chemical Analysis:** Full spectrographic verification - **Hardness Testing:** Core hardness verification - **Microstructural Analysis:** Grain size, inclusion rating - **Hardenability Testing:** Jominy test if specified ### **Nitriding Process Control** - **Case Depth Verification:** Microhardness traverse per ASTM E384 - **White Layer Measurement:** Microscope examination - **Surface Hardness:** Rockwell or Vickers testing - **Adhesion Testing:** Scratch or indentation tests if required ### **Non-Destructive Testing** - **Magnetic Particle:** For surface defects pre- and post-nitriding - **Liquid Penetrant:** For surface-breaking defects - **Ultrasonic Testing:** For internal quality assessment - **Dimensional Verification:** Before and after nitriding ### **Certification Levels** - **Standard MTR:** Chemistry and hardness only - **Full Certification:** Includes mechanical test results - **Process Certification:** Includes nitriding process records - **Traceability:** Full heat-to-part tracking available ### **Latrobe Quality Enhancements** - **Enhanced Cleanliness:** Superior to standard requirements - **Consistent Response:** Predictable nitriding behavior - **Technical Documentation:** Comprehensive support documentation - **Quality Systems:** ISO 9001, AS9100 certified --- ## **HANDLING & PROCESSING** ### **Pre-Nitriding Preparation** 1. **Cleaning:** Remove all oils, greases, and contaminants 2. **Masking:** Apply protective coatings to areas not to be nitrided 3. **Fixturing:** Use proper supports to minimize distortion 4. **Loading:** Ensure proper spacing for gas circulation ### **Post-Nitriding Handling** - **White Layer:** May be removed by light honing or polishing if required - **Cleaning:** Remove any process residues - **Inspection:** Complete dimensional and hardness checks - **Protection:** Apply rust preventive if not immediately assembled ### **Safety Considerations** - **Nitriding Process:** Proper ventilation and ammonia handling procedures - **Material Handling:** Standard steel handling precautions - **Machining:** Use appropriate PPE and dust control - **Heat Treatment:** Standard furnace safety procedures --- ## **AVAILABILITY & ORDERING** ### **Standard Forms & Sizes** - **Round Bars:** 1/4" to 12" diameter - **Square Bars:** 1/4" to 6" square - **Flat Bars:** Up to 4" thick × 12" wide - **Forgings:** Custom shapes and sizes - **Billets:** For further processing ### **Standard Conditions** - **Annealed:** For machining (187-229 HB) - **Heat Treated:** Quenched and tempered to specification - **Rough Machined:** To customer requirements - **Stress Relieved:** For dimensional stability ### **Special Processing** - **Pre-nitriding Heat Treatment:** To customer specifications - **Partial Processing:** Heat treatment only or nitriding only - **Testing Services:** Additional testing and certification - **Just-in-Time:** Scheduled delivery programs ### **Lead Time Guidelines** - **Stock Material:** 2-4 weeks - **Production Material:** 6-10 weeks - **Heat Treatment:** Additional 2-3 weeks - **Nitriding:** Additional 1-2 weeks - **Full Processing:** 10-16 weeks total --- ## **TECHNICAL SUPPORT** ### **Comprehensive Services** - **Material Selection:** Assistance with grade selection for specific applications - **Heat Treatment:** Development of optimal pre-nitriding cycles - **Nitriding Process:** Recommendations for process parameters - **Troubleshooting:** Assistance with processing or performance issues ### **Laboratory Services** - **Metallurgical Analysis:** Microstructure, case depth, hardness testing - **Failure Analysis:** Investigation of service failures - **Process Optimization:** Testing to optimize nitriding parameters - **Quality Verification:** Independent testing and certification ### **Training & Education** - **Material Characteristics:** Understanding 135M properties and processing - **Nitriding Technology:** Best practices for nitriding processes - **Application Engineering:** Design considerations for nitrided components - **Troubleshooting Workshops:** Problem-solving for common issues ### **Contact Information** **Latrobe Specialty Metals Technical Services** Phone: +1 (724) 537-7711 Email: technicalservices@latrobemetals.com Nitriding Specialists: Available for consultation Website: www.latrobemetals.com --- ## **COMPARATIVE ADVANTAGES** ### **vs. Other Nitriding Steels** | Property | 135M (A355-A) | Nitralloy N | 4140 Nitrided | 316 Stainless Nitrided | |----------|---------------|-------------|---------------|------------------------| | **Surface Hardness** | 68-72 HRC | 65-70 HRC | 55-60 HRC | 60-65 HRC | | **Case Depth Potential** | Deep | Deep | Moderate | Shallow | | **Core Toughness** | Good | Very Good | Excellent | Poor | | **Distortion** | Low | Low | Moderate | Very Low | | **Cost** | Moderate | High | Low | High | | **Primary Application** | General nitriding | Heavy duty | Moderate wear | Corrosion + wear | ### **Latrobe LSS™ 135M Advantages** - **Superior Consistency:** Tight chemistry control for predictable nitriding response - **Enhanced Cleanliness:** Better fatigue performance and surface finish - **Technical Expertise:** Comprehensive support from nitriding specialists - **Quality Assurance:** Enhanced testing and certification options - **Proven Performance:** Established track record in demanding applications ### **Selection Guidelines** - **For Maximum Surface Hardness:** Choose 135M or Nitralloy 135 - **For Maximum Core Toughness:** Choose 4140 or 4340 nitrided - **For Corrosion Resistance:** Choose stainless steel grades - **For Economic Balance:** 135M offers excellent performance-to-cost ratio - **For Specialized Applications:** Consult with Latrobe technical services --- ## **ENVIRONMENTAL & REGULATORY** ### **Environmental Impact** - **Recyclability:** 100% recyclable as steel scrap - **Nitriding Process:** Modern controlled processes minimize environmental impact - **Coolant Management:** Proper disposal of machining coolants required - **Energy Efficiency:** Optimized processing for minimal energy consumption ### **Regulatory Compliance** - **RoHS Compliant:** Yes - contains no restricted substances - **REACH Registered:** Yes - fully compliant with EU regulations - **OSHA Compliance:** Standard steel handling and processing regulations apply - **International Standards:** Meets global specifications and requirements ### **Safety Data** - **MSDS Available:** Material Safety Data Sheet upon request - **Handling Precautions:** Standard steel handling procedures - **Nitriding Process Safety:** Special procedures for ammonia handling - **Disposal:** Scrap material should be recycled through proper channels --- ## **DISCLAIMER** ### **Important Notices** 1. **Technical Data:** The information provided represents typical values and characteristics. Actual properties may vary based on specific processing, heat treatment, nitriding parameters, and testing methods. 2. **Nitriding Process Dependence:** Final properties are highly dependent on proper pre-nitriding heat treatment and nitriding process control. 3. **Application Suitability:** Users should evaluate material suitability for specific applications, including all service conditions and requirements. 4. **Safety Responsibility:** Users are responsible for implementing appropriate safety procedures when handling, machining, heat treating, and nitriding this material. 5. **Intellectual Property:** This datasheet contains proprietary information of Latrobe Specialty Metals. Unauthorized reproduction or distribution is prohibited. ### **Warranty Information** Latrobe Specialty Metals warrants that material supplied will meet the chemical and physical specifications agreed upon at the time of order. Final performance in specific applications depends on proper processing by the customer, including but not limited to heat treatment, nitriding, machining, and fabrication. Consultation with Latrobe technical staff is recommended for critical applications. ### **Revision Information** **Document Number:** LSS-135M-DS-2024-01 **Effective Date:** January 2024 **Supersedes:** All previous versions **Next Review Date:** January 2025 --- *© 2024 Latrobe Specialty Metals. All rights reserved.* *LSS™ is a trademark of Latrobe Specialty Metals.* *ASTM A355 is a standard of ASTM International.* **Latrobe Specialty Metals** A TimkenSteel Company 2626 Ligonier Street Latrobe, PA 15650 USA Phone: +1 (724) 537-7711 www.latrobemetals.com -:- For detailed product information, please contact sales. -: Latrobe LSS™ 135M Nitriding Steel (ASTM A355 Class A) Specification Dimensions Size： Diameter 20-1000 mm Length <6473 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: Latrobe LSS™ 135M Nitriding Steel (ASTM A355 Class A) Properties -:- For detailed product information, please contact sales. -:

Applications of Latrobe LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A) -:- For detailed product information, please contact sales. -: Chemical Identifiers Latrobe LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A) -:- For detailed product information, please contact sales. -:

Packing of Latrobe LSS™ 135M Nitriding Steel Flange (ASTM A355 Class A) -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Flange drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2944 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition