30CrMnSi is a chromium–manganese–silicon alloy structural steel known for its high strength, excellent toughness, and reliable hardenability after heat treatment.
This steel grade delivers a balanced combination of strength, impact resistance, and fatigue performance, making it widely used in automotive, aerospace, defense, and heavy machinery industries.
The material offers better tensile and yield strength than medium-carbon steels while maintaining good machinability and weldability when properly heat-treated. It is particularly suitable for forged or quenched and tempered parts operating under dynamic loads.
Chemical Composition (% by weight)
C: 0.28–0.34
Si: 0.90–1.20
Mn: 0.70–1.00
Cr: 0.80–1.10
P: ≤ 0.030
S: ≤ 0.030
This carefully controlled alloying system ensures fine-grain microstructure, excellent mechanical uniformity, and stable hardenability across cross-sections.
Mechanical Properties (Typical After Quenching & Tempering)
| Property | Typical Value |
|---|---|
| Tensile Strength | 980–1180 MPa |
| Yield Strength | ≥ 785 MPa |
| Elongation | ≥ 10% |
| Reduction of Area | ≥ 40% |
| Impact Toughness | ≥ 35 J |
These properties make 30CrMnSi suitable for high-load, impact-resistant parts, especially those requiring both toughness and fatigue resistance.
Key Features and Advantages
High tensile and yield strength with stable hardenability
Reliable impact and fatigue resistance under cyclic loading
Good wear resistance after quenching and tempering
Machinable and weldable with proper preheat and postheat control
Uniform mechanical performance through cross sections
Typical Industrial Applications
30CrMnSi alloy steel is widely used in manufacturing load-bearing and dynamic parts across several industries:
Aircraft landing gear components and structural parts
Automotive drive shafts, connecting rods, and transmission gears
Heavy-duty bolts, studs, and fasteners
Mechanical couplings and machine tool spindles
Forged structural parts for mining and construction equipment
Equivalent Standards:
GB/T 3077: 30CrMnSi
DIN: 30CrMnSi5
JIS: SCM435 (approximate)
ASTM: A29 4130 (comparable mechanical behavior)
Precision Supply from ChinaSpecSteel
ChinaSpecSteel provides 30CrMnSi alloy structural steel produced by Jiyuan Iron & Steel Group, a leading Chinese manufacturer specializing in special quality bar and alloy steels.
Jiyuan operates a long-process integrated production system, from ironmaking and steelmaking to hot rolling and precision testing. This ensures consistent chemical composition, excellent cleanliness, and reliable mechanical stability in every batch.
Available Supply Forms:
Hot-rolled and forged bars, billets, and discs
Normalized, quenched & tempered, or annealed delivery conditions
Machining blanks and OEM-specific dimensions
Certified mill test reports (EN 10204/3.1)
Third-party inspection (SGS, BV, TÜV) available upon request
Manufacturing Excellence — Jiyuan Iron & Steel
Jiyuan Iron & Steel serves as one of China’s most advanced and comprehensive special steel production bases, featuring state-of-the-art refining, continuous casting, and rolling facilities.
Its process and quality control meet international metallurgical standards, producing steel with fine grain, low inclusion, and superior mechanical integrity.
The company’s main product portfolio includes:
Bearing steel, spring steel, gear steel, cold heading steel
Alloy and carbon structural steels, high-strength wear-resistant steel
Tube billet and anchor chain steel
Deep-processed products: precision wire, heat-treated bars, bright bars, and fasteners
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