In the world of alloy steel, few materials offer the balance of strength, toughness, and reliability that 42CrMo4+QT delivers. It’s more than a steel grade—it’s a mission-critical solution for components under extreme mechanical stress.

At Behari Lal Engineering Limited (BLEL), a trusted name among QT steel manufacturers in India, we specialize in producing heat-treated steel bars designed for high-performance engineering applications across automotive, aerospace, energy, and heavy machinery sectors.

What Is 42CrMo4+QT?

42CrMo4+QT is a quench and tempered (QT) chromium-molybdenum alloy steel known for its high tensile strength, exceptional toughness, and fatigue resistance. It’s widely used in components where performance under load, pressure, and dynamic stress is non-negotiable.

Common Applications:

• High-strength bolts and fasteners
• Gears and pinions
• Transmission shafts
• Crankshafts and connecting rods
• Engine and drive components

Its excellent wear resistance and mechanical integrity make it a preferred choice for industries requiring reliability in harsh environments.

Chemical Composition of 42CrMo4

Element	Content (%)
Carbon (C)	0.38 – 0.45
Silicon (Si)	0.60 – 0.90
Manganese (Mn)	0.60 – 0.90
Chromium (Cr)	0.90 – 1.20
Molybdenum (Mo)	0.15 – 0.30
Phosphorus (P), Sulfur (S)	Trace

This balanced Cr-Mo composition enables deep hardenability, thermal resistance, and excellent response to heat treatment.

What Does QT Mean in Steel?

QT stands for Quenching and Tempering, a dual-step heat treatment process that significantly enhances mechanical properties:

• Quenching: Steel is heated to ~840–880°C and then rapidly cooled (in oil or water) to form a hard martensitic microstructure.
• /strong>Tempering: The hardened steel is reheated to ~500–650°C to reduce brittleness, relieve internal stresses, and improve toughness.

At BLEL, we use state-of-the-art furnaces and precision thermal control systems to achieve uniform hardening across the full cross-section of each steel bar or forging.

Key Benefits of 42CrMo4+QT Alloy Steel

1. High Strength and Hardness

The QT process boosts yield strength and tensile properties, enabling the material to withstand static and dynamic loading.

2. Excellent Toughness and Fracture Resistance

Tempered martensitic structure enhances impact and fatigue resistance, ideal for safety-critical rotating or load-bearing parts.

3. Superior Machinability

Despite its strength, 42CrMo4+QT offers good machinability for turning, drilling, and milling—saving time and tools during downstream processing.

4. Outstanding Fatigue Performance

A fine grain structure with low inclusion levels helps resist crack initiation under cyclic stresses, extending component life.

Industrial Applications of 42CrMo4+QT

This alloy steel is widely used in sectors including:

• Automotive OEMs and Tier-1 suppliers
• Railway crankshafts and axles
• Forging dies and tooling
• Agricultural and construction machinery
• Powertrain and gear systems

Its ability to resist torque, pressure, vibration, and thermal cycling makes it indispensable in modern mechanical design.

QT Steel Manufacturing at BLEL

As one of the leading QT steel manufacturers in India, Behari Lal Engineering Limited offers:

• Round, forged, and machined bars in 42CrMo4+QT and other grades
• Fully integrated manufacturing with in-house heat treatment
• ISO-certified processes and test certifications
• Custom mechanical properties, sizes, and surface finishes
• Microstructure validation, hardness mapping, and batch traceability

Whether you need bars for shafts, spindles, or specialized engineering applications, BLEL ensures every piece of steel meets exacting performance criteria.

Why BLEL for 42CrMo4+QT?

At BLEL, we don’t just supply steel—we engineer it for performance. Our deep metallurgical expertise, combined with modern quench-and-temper lines and strict process control, guarantees:

• Uniform properties from core to surface
• Repeatable performance across batches
• Compliance with global material and dimensional standards

Looking for Reliable QT-Treated Alloy Steel?

42CrMo4+QT is the go-to steel for components that can’t afford to fail—and Behari Lal Engineering Limited is the partner that ensures they won’t.

Contact us today to discuss your specifications, request a quote, or explore how BLEL can supply QT steel solutions tailored to your toughest engineering demands.

Tags/Keywords:

42CrMo4+QT steel, QT steel manufacturers India, quench and tempered steel, CrMo alloy steel bars, heat treated steel bars, high strength steel India, BLEL, QT round bar suppliers, alloy steel for automotive parts