SHE 15b4h boron steel

Introduction

We manufacture forging ingots, billets, and blooms in boron-alloyed carbon steel specifically for 15b4h, designed for high hardenability and consistent mechanical performance in heat-treated engineering applications. 15b4h is a low carbon boron steel developed to achieve high hardenability with minimal alloy additions. The controlled addition of boron significantly enhances hardenability, allowing the steel to attain uniform strength and hardness after quenching, even in larger sections. This grade is widely used in automotive and general engineering applications where good toughness, reliable strength, and cost-effective heat treatment performance are required. 15b4h is particularly suitable for mass-produced forged and machined components. 15b4h offers an optimal balance of machinability in the annealed condition and excellent response to quenching and tempering, making it a preferred choice for structural and safety-related parts.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.12 – 0.18 Provides base strength and toughness
Manganese (mn) 0.60 – 0.90 Improves hardenability and strength
Silicon (si) 0.15 – 0.35 Increases strength and elasticity
Boron (b) 0.0005 – 0.003 Significantly enhances hardenability
Phosphorus (p) Max 0.025 Impurity; controlled to maintain toughness
Sulphur (s) Max 0.025 Impurity; controlled for machinability
Chromium (cr) Max 0.30 Residual element
Nickel (ni) Max 0.30 Residual element
Molybdenum (mo) Max 0.08 Residual element

Mechanical properties (typical – quenched & tempered)

  • tensile strength: 600 – 800 MPa
  • yield strength: 450 – 600 MPa
  • hardness: 18 – 28 hrc
  • impact toughness: good
  • fatigue resistance: good (properties may vary depending on section size and heat treatment conditions)

Heat treatment

  • annealing: used to soften the steel and improve machinability prior to final processing.
  • quenching: heating to approximately 850 – 900°c followed by rapid quenching to achieve a hardened structure.
  • tempering: reheating to a controlled temperature to relieve internal stresses and achieve the required balance of strength and toughness. The presence of boron allows lower alloy content while still achieving excellent hardenability after heat treatment.

Key features and benefits

  • Excellent hardenability due to boron addition
  • Uniform Mechanical properties across sections
  • Good toughness after heat treatment
  • Cost-effective alternative to higher alloy steels
  • Good machinability in annealed condition
  • Ideal for forging and mass production components

Typical applications

  • Automotive forged components
  • Suspension and chassis parts
  • Shafts and pins
  • Fasteners and structural parts
  • General engineering components
  • Heat-treated mechanical parts

Equivalent steel grades

15b4h has several international equivalents, including:

  • EN 15B4 – European standard
  • DIN 15B4 – German standard
  • IS 4432 – 15B4 type – Indian standard

Why Choose SHE 15B4H For Your Application?

SHE 15B4H Is An Excellent Choice When High Hardenability And Strength Are Required Without The Cost Of High Alloy Steels. The Addition Of Boron Allows Deeper And More Uniform Hardening, Making It Suitable For Thicker Sections And Critical Components. It Offers Consistent Performance, Improved Durability, And Cost Efficiency In Heat-Treated Applications.

Comparison table for similar grades

Grade Carbon (%) Key applications Heat treatment Comments
15b4h 0.12 – 0.18 Automotive forgings, structural parts Quenching & tempering Excellent hardenability due to boron
C15 0.12 – 0.18 General engineering parts Carburizing / normalizing Lower hardenability
16MnCr5 0.14 – 0.19 Case-hardened gears Carburizing Higher alloy cos

Summary

15b4h is a low carbon boron steel optimized for quench and temper applications. It offers a cost-effective combination of strength, toughness, and hardenability, making it a dependable material for automotive and general engineering industries.