Description: BBN steel is a well-known steel manufacturer and service provider in China, GB T-3077 40Cr Alloy Steel Plate is our superior product, we are favored by customers with high quality, competitive price and excellent service
Payment Terms: L/C, T/T, D/P, Western Union, Paypal, Money Gram
Good Hardenability40Cr delivers reliable hardenability and uniform properties after quenching and tempering, ideal for medium-load dynamic components.
Comprehensive PropertiesAfter heat treatment it offers an excellent combination of strength, toughness and wear resistance at moderate cost.
Widely UsedOne of the most popular alloy steel grades for gear blanks, shafts, fixtures and connectors in machinery worldwide.
01Product Overview & Specifications
GB/T 3077 40Cr is a widely used Chinese chromium-alloyed quenched-and-tempered structural steel for general engineering and mechanical manufacturing. Belonging to the chromium-alloyed heat-treatable family, it features good hardenability, comprehensive mechanical properties after heat treatment, moderate cost and abundant supply.
It is one of the most popular alloy steel grades for mechanical component production across domestic and overseas markets. After quenching and tempering it delivers excellent strength, wear resistance and impact toughness, supplied as hot-rolled alloy steel plates with complete MTC certificates.
Promptly (Stock) / Custom production: 10 – 40 working days
Certification
Mill Test Certificate (MTC) Available, third-party inspection supported
Payment Terms
T/T, L/C At Sight
Processing Services
Custom cutting, flattening, fine processing and third-party quality inspection
02Equivalent International Steel Grades
40Cr (SCr440) is a mainstream chromium-alloyed structural steel with widely used international equivalent grades, ensuring reliable cross-standard substitution for global mechanical manufacturing projects.
Standard System
Equivalent Grade
GB/T 3077 (China)
40Cralso SCr440
JIS (Japan)
SCr440
DIN (Germany)
41Cr41.7035
AISI (USA)
5140
Note: These equivalent grades share the 0.40% C / chromium-alloying concept and comparable hardenability, yet differ in impurity limits, testing and certification. For design-critical applications, verify detailed specifications before substitution. BBN technical team can assist with grade matching.
03Grade Designation & Meaning
The GB/T 3077 designation 40Cr encodes the carbon level and the alloying element of this chromium-alloyed steel.
40
40 — Carbon Content
Indicates a mean carbon content of approximately 0.40% (100 × C%) for good strength after hardening.
Cr
Cr — Chromium
Chromium improves hardenability, hardness and wear resistance of the heat-treated steel.
No Mo
No Mo — Cost Advantage
Unlike Cr-Mo grades, 40Cr contains no deliberate molybdenum, keeping cost moderate and supply abundant while remaining well suited to medium-load parts.
Q&T
Q&T — Heat Treatment
Supplied quenched & tempered for a comprehensive balance of strength, toughness and wear resistance.
40Cr vs Cr-Mo grades: 40Cr is a chromium-only alloyed grade without intended molybdenum. This gives it moderate cost and abundant supply, with slightly lower hardenability and temper resistance than Cr-Mo grades — an ideal choice for medium-load, high-strength mechanical structural parts.
04Chemical Composition
Cast analysis limits of 40Cr per GB/T 3077 (values in %, unless a range is given). Cu, Mo and Ni are maximum impurity limits, not deliberate additions.
Element
Content (%)
C (Carbon)
0.37 – 0.44
Si (Silicon)
0.17 – 0.37
Mn (Manganese)
0.50 – 0.80
P (Phosphorus)
0.035 max
S (Sulfur)
0.035 max
Cr (Chromium)
0.80 – 1.10
Cu (Copper)
0.30 max
Mo (Molybdenum)
0.15 max
Ni (Nickel)
0.30 max
Note: Values per GB/T 3077 cast analysis. Chromium provides the hardenability and wear resistance that distinguish 40Cr from plain-carbon grades. The exact heat analysis of each batch is stated in its Mill Test Certificate (MTC).
05Mechanical Properties
Mechanical properties of 40Cr after quenching and tempering (reference values per GB/T 3077; test sample size 25 mm; actual results depend on section size and heat-treatment parameters).
Mechanical properties of 40Cr (GB/T 3077, sample size 25 mm):
Grade
Yield Rp0.2 (MPa, min)
Tensile Rm (MPa, min)
Elongation A (%)
Reduction of Area Z (%)
Impact (J)
Hardness HB
40Cr
785
810
9
45
47
≤207 (annealed / high-temp tempered)
Note: 40Cr is a heat-treatable steel; the strength, elongation, reduction of area and impact values above are achieved after quenching and tempering and vary with section thickness and treatment. Hardness under annealed / high-temperature tempered condition is ≤207 HB; typical hardness after quenched & tempered treatment reaches about 25 HRC. Exact values are confirmed in the MTC.
06Product Types, Processing & Service
BBN Steel supplies full-specification 40Cr alloy steel plates with complete MTC certificates, supporting custom cutting, flattening, fine processing and third-party quality inspection for global mechanical manufacturing projects.
1
Alloy Steel Plate
Hot-rolled plates 5–120 mm thick, 1000–4000 mm wide, 3000–18000 mm long; customizable fixed length.
2
Cutting & Flattening
Custom cutting to size, flattening and edge preparation per your drawings.
3
Fine Processing & Inspection
Machining, fine processing and third-party quality inspection with full MTC traceability.
1
Fast Delivery
Common sizes shipped promptly from stock; custom production 10–40 working days.
2
MTC & Inspection
Mill Test Certificates available; third-party quality inspection supported.
3
Flexible Payment
T/T and L/C at sight accepted for your convenience.
4
Tech Consultation
Grade matching and processing advice from our sales & technical team.
GB/T 3077 40Cr alloy steel plates, 5–120 mm thickness, 1000–4000 mm width, 3000–18000 mm length
Custom cutting, flattening, fine processing and third-party inspection supported
MTC available, sufficient stock, flexible delivery cycles for global projects
Get Your GB/T 3077 40Cr Steel Plate Quotation Now
Send us your dimensions (thickness × width × length or cut size), quantity, heat-treatment and hardness requirements. We will reply with stock status, competitive factory price, delivery time and complete certification within 24 hours.
BBN Steel has established a complete set of production and supplier management system processes to ensure the improvement of product quality and better service to users.
Production Control
BBN Steel has established a complete production quality control process to ensure every link from research and development to mass production.
Supplier management
Our supplier selection will consider factors such as health and safety, ethics, environmental protection, price and quality to better serve customers.
Certification & Patent
We have successively won various international authoritative certifications, GB /T19001-ISO9001: 2000 quality management system was implemented.
After sales service
We provide booking space, shipping tracking service and after-sales service, we will always be first-class products and perfect pre-sale and after-sales service.
Get in Touch
Welcome to contact us through online consulting, emails and hotline if you are interested in our company or products. Our staff will reply you within 24 hours.
Address: HIGH-TECH DEVELOPMENT ZONE, ZHENGZHOU, CHINA
