Gear Materials Steel Round Bar

Gear materials steel round bar is a general term for steel that can be dry-processed to manufacture gears. Any steel that can be used to add gears can be called gear steel. Dry gears rely on the structural size and material strength of the wooden body to withstand external loads. Therefore The steel for manufacturing gears requires high strength, hardness, toughness, wear resistance, and manufacturability. With the development of technology, gear steel is moving towards high performance, long life, stable gear operation, low noise, safety, Develop in the direction of low cost, easy processing, and multiple varieties.

Gear materials steel round bar is a general term for steel that can be used to process and manufacture gears. Generally, there are low-carbon steels such as 20# steel, low-carbon alloy steels such as 20Cr and 20CrMnTi, medium-carbon steels such as 35# steel and 45# steel, medium-carbon alloy steels such as 40Cr and 42CrMo and 35CrMo, which can all be called gears. Usually, it has good strength, hardness and toughness after heat treatment according to the requirements of use, or the surface is wear-resistant, and the core has good toughness and impact resistance.

performance index：

Gear materials steel round bar requires good strength, hardness, etc. In terms of performance indicators, there are three main standards for measuring the performance of gear steel.

1. Hardenability.

The hardenability of gear steel is mainly to ensure the hardness of the core of gears of different sizes, which is beneficial to control the heat treatment deformation of gears. Its performance mainly depends on its chemical composition and its uniformity.

2. Oxygen content.

The oxide and sulfide inclusions and harmful elements in the steel will reduce the mechanical properties of the steel and affect the life of the gear. Therefore, the general gear steel requires the oxygen content to be controlled below 20x10-6.

3. Grain size.

The grain size index can improve the fatigue performance of the gear and reduce the deformation of the gear after heat treatment. The grain size of the general gear steel is required to be 26, which is mainly achieved by controlling the residual aluminum content in the steel to refine the grain during smelting.

The commonly used materials for gear steel are forged steel and cast steel. Among them, cast steel is generally used in the manufacture of gears with a diameter greater than 400mm and a complex structure that is not suitable for forging. In other cases, forged steel is more suitable. The forged steel used is based on The tooth surface hardness is also different.

 Among them, cast steel is generally used to manufacture gears with a diameter greater than 400mm, complex structures, and unsuitable forging. In other cases, forged steel is more suitable. The forged steel used is also different according to the hardness of the tooth surface:

1). Soft Tooth Surface

Tooth surface hardness less than 350mm is called soft tooth surface. The commonly used gear steel for soft tooth surface is 45# steel, 35SiMn, 40Cr, 40CrNi, 40MnB.

2). Hard tooth surface

Tooth surface hardness greater than 350mm is called hard tooth surface. Gear steel for hard tooth surfaces can be divided into medium carbon steel and low carbon steel. Medium carbon steel includes 35# steel, 45# steel,

40Cr, 40CrNi, 42CrMo, 35CrMo, etc. Low carbon steel includes 20Cr, 20CrMnTi, 20MnB, 20CrMnTo, etc.

Application of Gear materials steel round bar:

High hardenability, with carburized hardened and wear-resistant core surface and toughness, high low temperature impact toughness, good after medium welding, cutting and normalizing. Important parts for high speed, medium or heavy load, shock and friction, such as gears, gears, gear shafts, crossheads, etc.

1) 42CrMo gear steel has the characteristics of high strength, high hardenability, good toughness, small quenching deformation, high creep strength and high temperature durable strength.

It is used to manufacture forgings that require higher strength and larger quenched and tempered sections than 35CrMo steel, such as: large gears for locomotive traction, supercharger transmission gears, pressure vessel gears, rear axles, extreme load connecting rods and springs, etc. Oil deep well drill pipe joints and fishing tools below 2000m; can be used for molds such as bending machines.

2) 20CrMnTiH gear steel is a carburizing steel with good performance, high hardenability, hard and wear-resistant surface after carburizing and quenching, tough core, high low-temperature impact toughness, medium weldability, and good weldability after normalizing Machinability.

It is used to manufacture important parts with a section <30mm that withstand high speed, medium or heavy load, impact and friction; such as: gears, ring gears, gear shaft crossheads, etc. It is a substitute steel for 18CrMnTi, widely used as carburized parts. Used in the automobile and tractor industries with a section below 30mm; it is an important carburized part that withstands high speed, medium or heavy load and withstands impact and friction.

The national standards for gear materials steel round bar may vary from time to time and from region to region. The following are some of the more common national standards

Chinese standard:

China's current gear steel standards mainly include GB/T 3077-2015 "Alloy Structural Steel",

GB/T 5216-2014 "Guaranteed Hardenability Structural Steel"

YB/T 037-2005 "High-quality Structural Steel Cold-drawn Flat Steel "wait.

British Standard:

BS EN 10083, which covers technical delivery conditions for alloy structural steels; BS EN ISO 683, which is a series of standards for hot-rolled steel products

American standard:

ASTM A322 This standard covers the specification of alloy steel bars, round bars, and shapes.

Japanese standard:

JIS G 4053 This standard includes some standard specifications for low alloy steel bearing steel and alloy structural steel.

The steel used in the manufacture of gears is required to have high strength, hardness, toughness, wear resistance and manufacturability, and should meet the standard requirements.

Out of roundness:
The out-of-roundness of round steel should not be greater than 75% of the nominal diameter tolerance.

Length:
Round steel is 2m ~ 10m, and its allowable deviation is +50mm.

Curvature:
The bending degree per meter of round steel should not be greater than 6mm, and the total bending should not be greater than 0.6% of the total length.

Pokou:
The bevel at both ends of the round bar shall not be greater than 30% of the nominal diameter of the round bar.