专业材成英语 (2)

Hardness is a very important property since the manufacturing depends on it to a great extent. 硬度是非常重要的性能，因为制造在很大程度上依赖与他， Hardness is the resistance offered by a material indentation. Moh的scale of hardness is based on ten standard minerals as shown in Table 2.1. 硬度是材料对压力的抵抗力莫氏硬度测量基于表2.1所示的十种标准矿物。

It can be measured by the indentation made by a harder material. . 通常可以由一种坚硬的材料造成的压痕来测量。

The indentation made depends upon the applied load, the sharpness of the indentor and the time for which the applied load is maintained压痕取决于所施加负载，压痕的清晰度取决于负载应用的时间。

There are a number of indentation tests to measure the hardness of a material normally. 同场还有许多硬度测试方法来测量材料的硬度。

These usually involve a ball, a cone or a pyramid of a harder material which is indented into the material under test with a specified load. 这些测试方法通常是在指定的负载下把由坚硬的材料制成的团块、圆锥体或球椎体压入材料，The permanent indentation thus made is measured to give an indication ofthe hardness on the given scale for the tests.偶测量这些所产生的永久压痕来在测试给定的范围内对材料的硬度做出指示。

Some precautions that need to be taken during the use of Brinell test are that the surface of the material whose hardness is being tested should be smooth and even, and there is enough material underneath the indentation and on all sides to give a proper value for the indentation. 一些预防措施,需要在使用布氏硬度试验是材料的表面的硬度测试应光滑、均匀,并有足够的材料在压痕和在各方面给予适当的缩进值。

The Brinell hardness of steel is roughly related to the tensile strength of the material utilizing the following empirical relationship for plain carbon steels. 这个布氏硬度的钢大致与抗拉强度的材料利用以下实证关系碳素钢。

It may be noted that these conversions are only approximate. 可以指出,这些转换只是近似。

Also, the actual relationship depends upon the chemical composition of the alloy as well as the heat treatment process. 同时,实际的关系取决于合金的化学成分和热处理工艺。

Comparative values for these are given in Table 2.2. 比较值在表2.2中给出了这些。

There are number of indentation tests to measure the hardness of a material normally.通常还有许多硬度测试方法来测量材料的硬度These usually involve a ball, a coneor a pyramid of a harder material which is indented into the material under test with a specified load. The permanent indentation thus made is measured to give an indication of the hardness on the given scale for the tests这些测试方法通常是在指定的负载下把由坚硬的材料制成的团块、圆锥体或球椎体压入材料，偶测量这些所产生的永久压痕来在测试给定的范围内对材料的硬度做出指示。

The most commonly used tests are the following: 最常用的测试有以下几种Brinell hardness test where a sphere (usually of diameter 10+0.01mm) made of steel or tungsten Carbide isindented with a gradually applied load at right angles to the specimen surface and the indentation diameter madeon the specimen measured.验Then the Brinell hardness number, BHN is given by 布氏强度是通过施加90°的压力在用钢或钨化物做成的试件表面,然后测试试件上压痕直接来获得的BHN=2p/D[D-√D2-d2]Where P is the applied load in kg, D is the diameter of the ball in mm, and d is the diameter of the indentation in mm其中，P是所施加的载荷千克， D是球的直径,毫米，和d为压痕的直径，用mm表示The applied load P is based on the hardness of the specimen material being tested. 所施加的载荷P是根据被测试的样品材料硬度Some precautions that need to be taken during the use of Brinell tests are that the surface of the material whose hardness is being tested should be smooth and even, and there is enough material underneath the indentation and on all sides to give a proper value for the indentation. 贝氏硬度的测试使用过程中要采取某些预防措施，需要被测试的材料的硬度，表面应是光滑和均匀的，并且压痕下应该有足够的材料，下面的压痕和各侧面，应该有一个适当的压痕值The Brinell hardness of steel is roughly related to the tensile strength of the material utilizing thefollow ingempirical relationship for plain carbon steels. 普通钢和布氏硬度相关的抗拉强度可利用下面的经验公式来表达Tensile strength (in MPa = 3.55 x BHN when BHN<≤175 Tensile strength (in MPa)= 3.38 x BHN when BHN > 175It may be noted that these conversions are only approximate. Also, the actual relationship depends upon the chemical composition of the alloy as well as the heat treatment process. Comparative values for these are given in Table 2.2. 可能需要注意的是这些转化都是相互的。

当然，实际关系依赖于合金化学成分和热处理工艺，这些比较值如2.2所示Rockwell tests utilize the principle that the depth of penetration of the indentor is proportional to the material hardness. 洛氏硬度运用的规律是压痕仪的渗透深度和材料的硬度成正比的 Thus, the hardness measurement is faster compared to other methods. 这样的硬度的测试和其他的方法相比快得多In the Rockwel test, a sphero-conical diamond cone of 120angle and a spherical apex of 0.2-mm radius is used to make the indentation, and the depth of the indentation, t, is used as a criterion to calculate the hardness number.洛氏硬度的测试是用一个成120°的金刚石球锥和直径为0.2mm的球形顶总来压痕，压痕深度t则用来作为计算硬度的一个标准The Rockwell hardness number (R) is given by 洛氏硬度值可以从下列式得出R = 100-500 t Depending on the load used for indentation there are a number of scales, A, B, C, etc., available in Rockwell tests. 依据压痕所加负载，适用于洛氏硬度测试的一系列数据范围可为A.B,C,等，These are used for materials with different hardnesses. 这些都是用于不同硬度的材料In the Rockwell B test. a steel ball of 0.06t5-inch diameter is used with a load of l00kg. 在洛氏B测试。