Comprehensive Overview of 4140 Steel Hardness

DONGGUAN, China - Jan. 17, 2024 - PRLog -- 4140 Steel Hardness Testing
1.Brinell Hardness Test: It is one of the most commonly used hardness testing methods. By applying a certain predetermined load on the surface of the steel, the diameter of the indentations of different depths formed is measured. According to the indentation diameter and test Load calculation hardness value.

2.Vickers Hardness Test: This method is a commonly used microhardness testing method represented by HV (Vickers hardness). A Vickers hardness testing machine is used to apply a certain load of diamond or hard alloy indenter to the surface of 4140 steel, measure the diagonal length of the indentation, and calculate the hardness value.

3.Rockwell Hardness Test: This method is a metal hardness test method represented by the HRC symbol, which measures the depth or union depth and rebound depth of the indentation formed on the surface of 4140 steel, and reads the hardness value based on the measurement.

4.Ultrasonic Hardness Test: It is a non-contact hardness testing method that uses the propagation speed and reflection characteristics of ultrasonic waves on the surface of steel to infer hardness. The hardness value is calculated by measuring the propagation time of ultrasonic waves in the material.

Answers to Customer Questions About 4140 Steel Hardness
Recently, our Songshun customer from Europe asked how the hardness of our 4140 steel is tested? 4140 steel was tested on a Rockwell C hardness tester. The measurement result was 25 to 29 HRC. Is it correct? Also, is the material that reaches this hardness range quenched and tempered or natural?

To sum up, when customers need to test 4140 steel hardness, we can provide several methods. Among them, in the Rockwell hardness test, two versions, HB or HRC, are usually used. When the customer measured 4140 steel hardness, the result was 25 to 29 HRC, which is correct. This hardness range can be achieved in the natural state, but there is no guarantee that the hardness can be achieved 100%. The general hardness range is 260–270HB, or 260–300HB. As the weather gets colder, the steel is air-cooled faster, and the surface hardness may reach 100%. However, the center hardness of the steel may be slower than the surface due to air cooling, so the interior may be lower than the surface hardness.