ASTM A424 Steel Sheet,Plate, type II, composition A

ASTM A424 Steel Sheet/Plate, type II, composition A, commercial quality Product Information -:- For detailed product information, please contact sales. -: ASTM A424 Steel Sheet/Plate, type II, composition A, commercial quality Synonyms -:- For detailed product information, please contact sales. -:

ASTM A424 Steel, type II, composition A, commercial quality Product Information -:- For detailed product information, please contact sales. -: # **Product Technical Datasheet: ASTM A424 Type II, Composition A - Commercial Quality Steel Sheet for Porcelain Enameling** ## **1. Product Overview** **ASTM A424 Type II, Composition A (Commercial Quality)** is a **conventional low-carbon steel sheet** specifically formulated for **two-coat porcelain enameling systems** requiring a ground coat followed by a cover coat. As a commercial quality (CQ) variant with defined Composition A chemistry, it provides a cost-effective substrate for applications where enamel adherence, thermal resistance, and chemical durability are priorities, but premium formability characteristics are not essential. This grade represents a balanced solution for industrial and architectural enameling applications. ## **2. Governing International Standard** - **Primary Standard:** **ASTM A424/A424M** - Standard Specification for Steel Sheet for Porcelain Enameling - **Standard Status:** Current active specification - **Type Classification:** Type II - For two-coat enameling systems - **Composition Designation:** Composition A - Specific chemistry range for ground coat adherence - **Quality Tier:** Commercial Quality (CQ) - Standard production quality - **Related Standards:** - **ASTM C286** - Terminology for Porcelain Enamel - **ASTM C347** - Test Method for Porcelain Enamel Adherence ## **3. Chemical Composition** Composition A represents a specific chemical balance optimized for ground coat adherence in two-coat systems: | Element | Required Range (%) | Typical (%) | Metallurgical Function | |---------|-------------------|-------------|------------------------| | **Carbon (C)** | 0.04 - 0.08 | 0.06 | Moderate level for economy; controlled to minimize fish-scaling | | **Manganese (Mn)** | 0.30 - 0.50 | 0.40 | Standard deoxidizer and solid solution strengthener | | **Phosphorus (P)** | 0.015 - 0.040 | 0.025 | **Critical:** Promotes enamel adherence via interface reactions | | **Sulfur (S)** | ≤ 0.040 | 0.025 | Controlled impurity; affects surface quality | | **Silicon (Si)** | Trace - 0.03 | 0.02 | Minimized to prevent silica-related enameling defects | | **Copper (Cu)** | 0.20 max (optional) | 0.10 | Optional for atmospheric corrosion resistance | | **Nickel (Ni)** | Not required | <0.05 | Residual; not intentionally added | **Key Composition Features:** - **Phosphorus Enhancement:** Specifically controlled (0.015-0.040%) to promote ground coat adherence through Fe-P-O interface layer formation - **Moderate Carbon:** Higher than premium grades but controlled to balance cost and fish-scaling risk - **No Mandatory Stabilizers:** Titanium/niobium not required for Type II compositions - **Conventional Deoxidation:** Typically aluminum-killed for consistent quality ## **4. Physical & Mechanical Properties** ### **Base Metal Properties (As-Supplied):** - **Tensile Strength:** 45 - 60 ksi (310 - 415 MPa) - **Yield Strength (0.2% Offset):** 30 - 40 ksi (205 - 275 MPa) - **Elongation in 2" (50 mm):** 28 - 38% - **Hardness (Rockwell B):** 55 - 75 HRB - **Yield Point Elongation:** May exhibit slight yield point (1-2%) - **Strain Hardening Exponent (n):** 0.18 - 0.22 ### **Formability Characteristics:** - **r-value (Normal Anisotropy):** 1.0 - 1.3 (moderate drawing capability) - **Minimum Bend Radius:** 1.5 × thickness for 90° bend - **Limiting Drawing Ratio (LDR):** 1.8 - 2.0 (moderate deep drawing) ### **Enameling Performance Properties:** - **Ground Coat Adherence:** Excellent (due to phosphorus content) - **Fish-Scale Resistance:** Good with proper firing cycle control - **Thermal Expansion Coefficient:** ~12.5 × 10⁻⁶/°C - **Firing Temperature Range:** 780 - 840°C (1436 - 1544°F) - **Warpage Resistance:** Good for moderate-sized parts ### **Physical Constants:** - **Density:** 7.85 g/cm³ - **Modulus of Elasticity:** 29 × 10⁶ psi (200 GPa) - **Poisson's Ratio:** 0.29 - **Thermal Conductivity:** 50 - 52 W/m·K ## **5. Manufacturing Process** ### **Production Route:** 1. **Steelmaking:** Conventional BOF or EAF 2. **Secondary Treatment:** Ladle argon stirring 3. **Continuous Casting:** Standard slab casting 4. **Hot Rolling:** Finish rolling ~900°C 5. **Pickling:** HCl or H₂SO₄ acid cleaning 6. **Cold Rolling:** 50-70% reduction 7. **Annealing:** Batch or continuous annealing 8. **Temper Rolling:** 0.5-1.5% extension ### **Quality Control Points:** - **Chemical Consistency:** Tight control of P, C, Mn within Composition A ranges - **Surface Quality:** Commercial surface finish standards - **Grain Size:** ASTM 6-8 (25-50 μm) - **Decarburization:** Minimal surface decarb allowed ## **6. Key Characteristics & Performance** ### **Enameling Advantages:** 1. **Superior Ground Coat Adherence:** Phosphorus promotes strong chemical bonding 2. **Good Thermal Resistance:** Suitable for repeated firing cycles 3. **Cost-Effectiveness:** Lower cost than premium enameling steels 4. **Process Tolerance:** Forgiving of normal enameling process variations 5. **Color Consistency:** Good ground coat provides uniform cover coat appearance ### **Forming Characteristics:** 1. **Moderate Formability:** Suitable for most common forming operations 2. **Consistent Springback:** Predictable behavior for tooling design 3. **Good Weldability:** Standard resistance welding compatible 4. **Adequate Strength:** Sufficient for structural enameled components ### **Limitations:** 1. **Limited Deep Drawability:** Not for severe drawing applications 2. **Fish-Scale Risk:** Requires careful firing cycle control 3. **Surface Imperfections:** May show more defects than premium grades ## **7. Typical Applications** ### **Architectural & Building:** - **Exterior Wall Panels:** Building facades and curtain walls - **Roofing Components:** Architectural roof panels - **Column Covers:** Structural column protection - **Signage:** Durable exterior signs ### **Appliance Industry:** - **Water Heater Tanks:** Ground coat for corrosion protection - **Range/Stove Components:** Oven liners and panels - **Commercial Appliances:** Restaurant equipment surfaces - **HVAC Components:** Heating system panels ### **Industrial Applications:** - **Chemical Processing Equipment:** Corrosion-resistant linings - **Storage Tanks:** Interior protective linings - **Laboratory Furniture:** Chemical-resistant surfaces - **Process Vessels:** Industrial equipment linings ### **Consumer Products:** - **Barbeque Grills:** Heat-resistant cooking surfaces - **Fireplace Inserts:** Decorative and protective panels - **Sanitaryware:** Bathtubs and sinks (commercial grade) ## **8. Porcelain Enameling Process** ### **Two-Coat System Requirements:** **Ground Coat Application:** - **Purpose:** Provides adherence base and corrosion resistance - **Thickness:** 0.10 - 0.15 mm (4 - 6 mils) - **Composition:** Cobalt/Nickel-bearing frit for adherence - **Firing Temperature:** 800 - 840°C - **Adherence Mechanism:** Fe-P-O interface layer formation **Cover Coat Application:** - **Purpose:** Provides color, gloss, and chemical resistance - **Thickness:** 0.15 - 0.25 mm (6 - 10 mils) - **Application:** Wet spray over fired ground coat - **Firing Temperature:** 780 - 820°C - **Final Properties:** Durable, chemically resistant surface ### **Process Parameters:** - **Surface Preparation:** Critical cleaning and pickling - **Drying Conditions:** Controlled humidity drying - **Firing Cycles:** Separate firing for each coat - **Cooling Rates:** Controlled to prevent thermal stress ## **9. Fabrication Guidelines** ### **Forming Operations:** - **Maximum Drawing Depth:** Limited to moderate draws - **Bend Allowance:** Standard carbon steel practices - **Tooling Requirements:** Conventional tool steels acceptable - **Lubrication:** Compatible with enameling pre-treatment ### **Cutting & Blanking:** - **Shearing:** Clean edges essential for enamel coverage - **Laser Cutting:** Produces excellent edge quality - **Punching:** Sharp tools with proper clearance - **Deburring:** Essential before enameling ### **Joining Methods:** - **Resistance Welding:** Spot welding before enameling - **Mechanical Fastening:** Compatible with enamel system - **Adhesive Bonding:** Epoxy systems for assembly ## **10. Quality Control & Testing** ### **Steel Quality Tests:** - **Chemical Analysis:** Verification of Composition A ranges - **Tensile Testing:** Periodic verification - **Bend Test:** 180° bend around 1× thickness - **Surface Inspection:** Visual for major defects ### **Enameling Performance Tests:** - **ASTM C347:** Adherence test (impact or bend) - **ASTM C538:** Color and gloss measurement - **ASTM C614:** Alkali resistance - **Thermal Shock:** Resistance to thermal cycling ## **11. Comparison with Other Grades** | Property | Type II Comp A CQ | Type I DQ | Type II Comp B | |----------|-------------------|-----------|----------------| | **Carbon Content** | 0.04-0.08% | ≤0.005% | 0.04-0.08% | | **Phosphorus** | 0.015-0.040% | Trace | 0.015-0.040% | | **Enamel System** | Two-coat | Single-coat | Two-coat | | **Formability** | Moderate | Excellent | Good | | **Adherence Mechanism** | Chemical (P-assisted) | Direct bond | Chemical (Ni-assisted) | | **Relative Cost** | Low | High | Moderate | ## **12. Economic Considerations** ### **Cost Factors:** - **Material Cost:** 20-30% lower than premium enameling steels - **Processing Cost:** Two-coat system increases processing steps - **Yield Impact:** Generally good production yields - **Tooling Cost:** Standard tooling acceptable ### **Value Proposition:** - **Reliable Performance:** Proven two-coat system technology - **Corrosion Resistance:** Excellent with proper ground coat - **Design Flexibility:** Suitable for moderately complex shapes - **Color Options:** Wide range of cover coat colors available ## **13. Storage & Handling** - **Storage Conditions:** Dry, indoor storage recommended - **Shelf Life:** 6-12 months with proper storage - **Surface Protection:** Light oil coating standard - **Handling:** Clean gloves to prevent contamination - **Stacking:** Flat with adequate support ## **14. Global Context & Equivalents** ### **International Standards:** - **Europe:** EN 10209 (modified for phosphorus content) - **Japan:** Similar concepts in JIS enameling standards - **General:** Commercial quality low carbon steel with specified P range ### **Market Position:** - **Mature Technology:** Well-established two-coat system - **Industry Acceptance:** Widely used in traditional enameling applications - **Evolution:** Basis for development of more advanced enameling steels ## **15. Limitations & Special Considerations** 1. **Not for Single-Coat Systems:** Specifically designed for two-coat applications 2. **Process Sensitivity:** Requires proper firing cycle control 3. **Thickness Limitations:** Best results in 0.6-2.0 mm range 4. **Forming Limits:** Not for severe deep drawing applications 5. **Surface Preparation:** Critical cleaning essential for success ## **16. Summary** **ASTM A424 Type II, Composition A (Commercial Quality)** represents a **traditional, cost-effective solution** for **two-coat porcelain enameling applications** requiring reliable ground coat adherence and good chemical resistance. Its specific phosphorus-controlled chemistry (0.015-0.040% P) provides **excellent enamel adherence** through chemical bonding mechanisms, making it particularly suitable for applications where corrosion resistance and durability are priorities. While offering more limited formability than premium drawing quality grades, this commercial quality variant provides **adequate performance for most standard enameling applications** at a **significantly lower cost point**. Its proven two-coat system technology delivers reliable results for architectural panels, appliance components, and industrial applications where the additional processing steps of a two-coat system are justified by the required performance characteristics. For manufacturers seeking a **balanced combination of performance and economy** in porcelain enameling applications, ASTM A424 Type II Composition A CQ offers a **practical, time-tested solution** that continues to serve numerous industrial and architectural markets effectively. -:- For detailed product information, please contact sales. -: ASTM A424 Steel, type II, composition A, commercial quality Specification Dimensions Size： Diameter 20-1000 mm Length <5892 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. -: ASTM A424 Steel, type II, composition A, commercial quality Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A424 Steel Sheet,Plate, type II, composition A, commercial quality -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A424 Steel Sheet,Plate, type II, composition A, commercial quality -:- For detailed product information, please contact sales. -:

Packing of ASTM A424 Steel Sheet/Plate, type II, composition A, commercial quality -:- 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 Sheet/Plate 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 2363 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