42CrMo Steel Plate: Complete Technical & Commercial Guide (English)
42CrMo is a premium Chinese standard (GB/T 3077-2015) medium-carbon chromium-molybdenum alloy structural steel plate known for its exceptional combination of high strength, toughness, and hardenability. It's widely used in heavy machinery, oil & gas, automotive, and mold manufacturing industries requiring reliable performance under high stress.
1. Basic Information & International Equivalents
| Specification |
Details |
| Chinese Standard |
GB/T 3077-2015 (Alloy structural steels) |
| Common Names |
42CrMo alloy steel plate, 42CrMo quenched and tempered plate |
| International Equivalents |
- ASTM A29/A29M: AISI 4140 (USA)- DIN EN 10083-3: 42CrMo4 (1.7225) (Europe)- JIS G4053: SCM440 (Japan)- ISO 683-13: 42CrMo4- AFNOR: 42CD4 (France) |
| Typical Delivery Condition |
Quenched and Tempered (Q&T), Normalized, or As-rolled |
2. Chemical Composition (GB/T 3077-2015)
| Element |
Content Range (%) |
Role |
| Carbon (C) |
0.38-0.45 |
Main strength contributor; ~0.42% (gives "42" in name) |
| Silicon (Si) |
0.17-0.37 |
Deoxidizer; improves strength and heat resistance |
| Manganese (Mn) |
0.50-0.80 |
Enhances hardenability and tensile strength |
| Chromium (Cr) |
0.90-1.20 |
Increases hardness, wear resistance, and corrosion resistance |
| Molybdenum (Mo) |
0.15-0.25 |
Boosts hardenability, high-temperature strength, and creep resistance |
| Phosphorus (P) |
≤0.035 |
Controlled impurity (reduces ductility if excessive) |
| Sulfur (S) |
≤0.035 |
Controlled impurity (reduces toughness if excessive) |
3. Mechanical Properties (Quenched & Tempered Condition)
| Property |
Minimum Value |
Test Standard |
| Tensile Strength (σb) |
≥1080 MPa |
GB/T 228.1 |
| Yield Strength (σs/σ0.2) |
≥930 MPa |
GB/T 228.1 |
| Elongation (δ5) |
≥12% |
GB/T 228.1 |
| Reduction of Area (ψ) |
≥45% |
GB/T 228.1 |
| Impact Energy (Akv) |
≥63 J (at -20°C, V-notch) |
GB/T 229 |
| Hardness |
217-286 HBW (after Q&T) |
GB/T 231.1 |
4. Key Characteristics & Advantages
Excellent Strength-Toughness Balance: Maintains ductility while providing ultra-high strength
Superior Hardenability: Can be heat-treated to achieve desired properties across thick sections
No Obvious Temper Brittleness: Stable performance after tempering
High Fatigue Resistance: Ideal for components under cyclic loading
Good Low-Temperature Toughness: Performs reliably in sub-zero environments
Machinability: Can be processed with standard machine tools (recommended after annealing)
Weldability: Requires preheating (200-300°C) and post-weld heat treatment to prevent cracking
5. Heat Treatment Guidelines
| Process |
Temperature |
Cooling Method |
Purpose |
| Quenching |
840-880°C |
Oil cooling |
Hardening to achieve base strength |
| Tempering |
540-680°C |
Air/water cooling |
Reducing brittleness while maintaining strength |
| Normalizing |
850-900°C |
Air cooling |
Homogenizing structure before final heat treatment |
| Annealing |
680-700°C |
Furnace cooling |
Softening for improved machinability (HB ≤217) |
| Surface Quenching |
900-950°C |
Induction/Flame |
Enhancing surface hardness (50-55 HRC) while retaining core toughness |
6. Typical Applications
42CrMo steel plate is widely used in manufacturing highly stressed components including:
Oil & Gas Industry: Drill pipe joints, wellhead equipment, pressure vessels, and offshore platform components
Automotive Industry: Drive shafts, gears, connecting rods, crankshafts, and suspension components
Heavy Machinery: Gearboxes, hydraulic cylinders, machine tool beds, and high-load structural parts
Mold Manufacturing: Large/medium plastic injection molds requiring strength and dimensional stability
Power Generation: Turbine components, generator shafts, and high-pressure steam pipes
Aerospace: Landing gear components and structural parts (after special heat treatment)
7. Standard Sizes & Supply Range
| Dimension |
Typical Range |
Notes |
| Thickness |
8 mm - 300 mm (custom up to 500 mm) |
20-80 mm is most common; >120 mm requires special forging |
| Width |
1500 mm - 4000 mm |
Standard: 2000/2200/2500 mm |
| Length |
6000 mm - 12000 mm |
Custom lengths available |
| Surface Finish |
Hot-rolled (black), shot-blasted, pickled, or painted |
According to customer requirements |
| Quality Grade |
I/II/III (ultrasonic testing available) |
For critical applications requiring internal integrity |
8. Commercial Product Description Template (For Export)
Product Name: 42CrMo Quenched & Tempered Alloy Steel Plate (GB/T 3077-2015, Equivalent to AISI 4140/DIN 42CrMo4)
Specifications:
Thickness: 25 mm
Width: 2200 mm
Length: 12000 mm
Heat Treatment: Quenched & Tempered (Q&T)
Surface: Shot-blasted and primed
Inspection: EN 10160 UT Class II, MTC 3.1 according to EN 10204
Key Advantages:
High tensile strength (≥1080 MPa) with excellent toughness
Full compliance with international standards (ASTM/DIN/ISO)
Stable supply from Baosteel/Tisco mill sources
Custom cutting, drilling, and machining services available
Packaging: Seaworthy wooden crates with moisture-proof paper and steel strapping
9. Quotation Inquiry Response Guide (For International Trade)
When responding to 42CrMo plate inquiries, emphasize these value points:
Material Certification: Provide MTC (Mill Test Certificate) 3.1, EN 10204 compliance, and ISO 9001 certification
Equivalent Assurance: Clearly state compatibility with AISI 4140/42CrMo4 for global acceptance
Quality Control: Highlight ultrasonic testing, chemical composition verification, and mechanical property testing
Supply Capacity: Mention monthly production volume and delivery lead time (typically 3-4 weeks)
Technical Support: Offer free material selection advice and heat treatment recommendations
Custom Solutions: Provide cutting-to-length, beveling, and surface treatment services
We will control the quality from part of material steel plate, each plate produced will be have it is own identify label, quality will check the chemical component and physical property and then provide material test certificate. Size dimension will be checked and show pictures to customer to guarantee all goods will be meet requirement.
Our company offers variety of products which can meet your multifarious demands. We adhere to the management principles of "quality first, customer first and credit-based", since the establishment of the company and always to do our best to satisfy potential needs of our customers. Our company is sincerely to willing to cooperate with enterprises from all over the world in order to realize a win-win situation since the trend of economic globalization has developed with irresistible force.
Q1: Why choose us?
A: Our company, as an internationally experienced and professional supplier, has been engaged in steel business for more than ten years. We can provide a variety of steel products with high quality to our clients.
Q2: Can you provide OEM/ODM service?
A: Yes. Please feel free to contact us for more details.
Q3:What is your terms of payment?
A: 100% T/T advance.
30% T/T and balance against copy of documents.
30% T/T advance, balance L/C at sight.
Q4: Can we visit your factory?
A: Warmly welcome. Once we have your schedule, we will arrange the professional sales team to follow up your case.
Q5: Can you provide sample?
A: Yes. Sample is free for regular sizes, but the buyer needs to pay freight cost.
Q6: How long is your delivery time?
A: Regular lead time is 15 to 30 days after receiving deposit.
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42CrMo Steel Plate: Complete Technical & Commercial Guide (English)
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