Description: BBN steel is a well-known steel manufacturer and service provider in China, GB/T 3077 20CR alloy steel 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
Excellent Surface Hardness20Cr delivers high surface hardness, wear resistance and a tough, impact-resistant core after carburizing and heat treatment — ideal for precision carburized components.
Superior WeldabilityIts low carbon content gives 20Cr noticeably better weldability than medium-carbon alloy steels, simplifying fabrication of welded structures.
Widely UsedA preferred material for precision transmission parts such as camshafts, gears, gear shafts, piston pins and claw clutches worldwide.
01Product Overview & Specifications
GB/T 3077 20Cr is a high-quality low-carbon low-alloy case-hardening (carburizing) structural steel specified under the GB/T 3077 standard. Belonging to the chromium-alloyed family with low carbon content, it features excellent surface hardness, wear resistance and core toughness after carburizing and heat treatment, plus superior weldability compared with medium-carbon alloy steels.
After carburizing and quenching it delivers a hard, wear-resistant surface with a tough core, supplied as hot-rolled alloy steel plates with complete MTC certificates for precision mechanical components.
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, heat treatment (carburizing / quenching & tempering), flattening, fine processing and third-party quality inspection
02Equivalent International Steel Grades
20Cr (SCr420) is a mature low-carbon chromium carburizing steel with widely used international equivalent grades of consistent chemistry and mechanical performance, suitable for cross-standard engineering substitution with technical confirmation.
Standard System
Equivalent Grade
GB/T 3077 (China)
20Cralso SCr420
JIS (Japan)
SCr420
ASTM (USA)
5120
EN / ISO
20Cr41.7027
BS (UK)
527A20
Note: These equivalent grades share the ~0.20% C / chromium-carburizing concept and comparable case-hardening performance, 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 20Cr encodes the low carbon level and the chromium alloying of this case-hardening steel.
20
20 — Low Carbon
Indicates a mean carbon content of approximately 0.20% (100 × C%), giving excellent weldability and a tough core after carburizing.
Cr
Cr — Chromium
Chromium improves hardenability, surface hardness and wear resistance of the carburized steel.
Carb
Carburizing — Surface Hardening
Low-carbon core designed for carburizing + oil quenching & tempering, yielding high surface hardness (~28–34 HRC) with a tough, impact-resistant core.
No Mo
No Mo — Cost Advantage
Like other chromium-only grades, 20Cr contains no deliberate molybdenum, keeping cost moderate and supply abundant while well suited to precision carburized parts.
20Cr vs medium-carbon alloy steel: 20Cr is the low-carbon carburizing variant. Its lower carbon gives superior weldability and a tougher core after case hardening, whereas medium-carbon chromium grades (e.g. ~0.40% C) are used where higher core strength from quench & temper is required. Both are chromium-only (no Mo).
04Chemical Composition
Cast analysis limits of 20Cr per GB/T 3077 (values in %, unless a range is given). Chromium is the principal alloying element; residual element limits follow the standard and are stated in the Mill Test Certificate.
Element
Content (%)
C (Carbon)
0.18 – 0.24
Si (Silicon)
0.17 – 0.37
Mn (Manganese)
0.50 – 0.80
P (Phosphorus)
0.030 max
S (Sulfur)
0.030 max
Cr (Chromium)
0.70 – 1.10
Note: Values per GB/T 3077 cast analysis. The low carbon (0.18–0.24%) is what makes 20Cr a carburizing grade with good weldability; chromium provides the hardenability and wear resistance that distinguish it from plain-carbon grades. The exact heat analysis of each batch is stated in its MTC.
05Mechanical Properties
Reference mechanical properties of 20Cr in the annealed / high-tempered (soft delivery) condition per GB/T 3077; test sample size as specified. After carburizing and oil quenching & tempering the hardened surface reaches about 28–34 HRC.
≥835 MPaMin. Tensile RmAnnealed / high-tempered
≥540 MPaMin. Yield Rp0.2Annealed / high-tempered
≥10%Elongation AMin. elongation
≥40%Reduction of Area ZMin. reduction
≥47 JImpact Absorbing EnergyCharpy, room temp
≤179 HBHardness (Annealed / High-Tempered)Surface ~28-34 HRC after oil Q&T
Mechanical properties of 20Cr (GB/T 3077, annealed or high-tempered condition):
Grade
Yield Rp0.2 (MPa, min)
Tensile Rm (MPa, min)
Elongation A (%)
Reduction of Area Z (%)
Impact (J)
Hardness HB
20Cr
540
835
10
40
47
≤179 (annealed / high-tempered)
Note: The strength, elongation, reduction of area and impact values above are GB/T 3077 reference values for the annealed / high-tempered (soft) delivery condition; the supplier controls delivery annealing hardness below 250 HB. After carburizing + oil quenching & tempering the case-hardened surface typically reaches 28–34 HRC with high wear resistance and a tough core. Exact values are confirmed in the MTC.
06Product Types, Processing & Service
BBN Steel supplies full-specification GB/T 3077 20Cr alloy steel plates with complete MTC certificates, supporting custom cutting, heat-treatment processing and third-party quality inspection for precision mechanical component projects worldwide.
1
Alloy Steel Plate
Hot-rolled plates 5–120 mm thick, 1000–4000 mm wide, 3000–18000 mm long; customizable fixed length.
2
Cutting & Heat Treatment
Custom cutting, flattening, and heat-treatment processing (carburizing / quenching & tempering) 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 20Cr alloy steel plates, 5–120 mm thickness, 1000–4000 mm width, 3000–18000 mm length
Custom cutting, heat treatment processing and third-party inspection supported
MTC available, sufficient stock, flexible delivery cycles for global projects
Get Your GB/T 3077 20Cr Steel Plate Quotation Now
Send us your dimensions (thickness × width × length or cut size), quantity, carburizing / 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
