布氏硬度试验与洛氏硬度试验

Hardness testing is one of the most widely used methods for evaluating materials. 在各种可用的技术中, the Brinell and Rockwell hardness tests stand out as the most common methods for assessing a metal's hardness and its resistance to wear. 在本文中, 我们经验丰富的专家, 李Mangham, will guide you through the 差异 between the Brinell and Rockwell hardness tests, 包括他们的方法, 优势, 差异, 并对评价材料硬度有实际意义.

What is The Difference Between The Brinell and Rockwell Hardness Tests?

While the two tests have similarities, there are several important 差异. Both test methods are suitable for the testing of soft and medium hard materials such as aluminum, 铜合金, 软钢. 而布里内尔的方法可以测试任何类型的金属, 它不能测量硬度大于650 HB.

The Rockwell test is considered easier to perform and has a shorter total testing time of 10-15 seconds than the Brinell test procedure which typically takes 30-60 seconds.

Many consider the results of the Brinell method to be more accurate and reliable, 特别是在测试粗糙材料时, 由于球形压头使压力分布更均匀. 在洛氏试验中, 如果样品的硬度不均匀, 三个压痕将测量样品的平均硬度, 哪些会影响整体的准确性.

什么是布氏硬度试验?

The Brinell hardness test (HBW) serves as a crucial scale for quantifying 材料硬度, 在ASTM E10和BS EN ISO 6506-1标准中定义. 

This test involves pressing a Brinell indenter against a test specimen under a specified load and time duration. 通常, 淬硬的钨钢球, 根据材料类型和球直径的不同，具有不同的力范围, 用于缩进. The load application spans 10 to 15 seconds, ensuring stability and accuracy. 随后，所产生的压痕是精心测量.

The Brinell test measures the width of the indentation using a microscope. This measurement is then converted into a Brinell hardness value – the ratio between the applied force and the surface of the indent – using the Brinell hardness scale.

布氏硬度试验的一些优点包括:

• 简单表面处理
• 易于测量打印直径
• More accurate and precise final measurements compared to Rockwell measurements
• 降低因设备故障而导致测试延迟的风险, particularly in contrast to the possibility of diamond cone breakage in Rockwell testing

“We find that the Brinell hardness test is usually our preferred method of testing if the customer requires highly accurate results and does not have a specified hardness method.”

什么是洛氏硬度试验?

Rockwell hardness testing is measured using the Rockwell hardness scale with the method defined in ASTM E18和BS EN ISO 6508-1.

Rockwell hardness testing is performed with an indenter of a specified size applied with a specified force for a fixed amount of time. A small Tungsten steel ball (HRBW method) is used to penetrate soft materials whilst a diamond cone (HRC method) is used for harder and heat-treated materials.

The test uses a preload to establish a zero position before the main load is applied. 然后主负载被拿走，只留下预负载. The Rockwell testing equipment then measures the distance traveled through the material.

不像布里内尔法, 洛克威尔的方法不测量印痕的大小, 而是压痕的深度. This measurement is then converted to a Rockwell hardness value directly on the machine.

洛氏硬度试验的一些优点包括:

• A Simpler planning stage than the Brinell test method which requires decisions, 比如选择合适的力, 待制作
• Faster results, with an immediate reading of hardness on the Rockwell device
• Shorter test duration at 10-15 seconds compared to the 30-60 seconds Brinell test procedure
• Less damage to the test specimen or material with the test leaving only a shallow imprint compared to the Brinell test method which leaves a large, 可见的痕迹.
  
  
  

布氏硬度到洛氏硬度的转换

The conversion scales for Rockwell and Brinell hardness are not consistent between non-austenitic and austenitic steels and should not be confused with one another. It is therefore important to be extremely careful when comparing Brinell hardness to Rockwell. ASTM E140 gives tables for conversions between the two hardness types and material types along with others such as Vickers and Knoop. It is also important to note that all hardness conversions are an approximation. 

“Selecting the most suitable test for the properties of the material and its intended application, and then carefully following the correct test protocol and procedures, 确保结果可靠的两个最重要的方法是什么.”

结论

Brinell and Rockwell hardness tests are valuable methods for evaluating 材料硬度，每个都有自己的优势和考虑. 而罗克韦尔测试提供了简单和快速的结果, the Brinell test is often favored for its perceived accuracy and reliability, 尤其是粗料. 最终, the choice between these methods depends on the specific requirements of the testing scenario and the properties of the material being evaluated.

At im体育APP we offer both Brinell and Rockwell hardness testing as part of its extensive portfolio of 机械测试服务. im体育APP’s laboratories can assist with custom or complex setups to suit specific needs and requirements, 由我们的专家指导您完成整个过程, from selecting and managing the most appropriate test procedure to evaluating the results. 有关硬度测试的更多信息，请 今日im体育APP.