追求卓异品质,打造民族精品。欢迎您来到高品质金刚石压头、硬度计知名生产企业—莱州市试验机金刚石工具厂

新闻资讯

热销产品

近期案例

  • TH140型里氏硬度计案例
  • MP-2T、XQ-2B等金相制样设备安装案例
  • HV-1000A(配图像处理系统)显微硬度计安装
  • HRS-150数显洛氏硬度计安装案例
  • HV-1000ASCCT图像处理显微硬度计安装案
  • 数显洛氏硬度计测试精度高、重复性好,获
  • MRG-480型高品质三目倒置金相显微镜图像
  • HVS-1000ATXY型自动步进平台显微硬度计
  • HV-1000ASCCT图像处理显微硬度计的安装
  • 安装调试HV-1000ACCT图像处理系统
  • HV-1000ASCCT显微图像处理系统案例
  • MRG-480型金相显微镜案例
  • 200HRS-150数显洛氏硬度计安装案例
  • HV-1000A型图像处理显微硬度计安装案例
  • 调试安装MP-2CE型金相磨抛机
  • HBS-3000型数显布氏硬度计安装案例
  • HVG-30维氏硬度计安装实例
  • P-2型金相试样磨抛机安装完成
  • 数显全洛氏硬度计
  • ZXQ-5型自动镶嵌机
  • HV-1000ACCT图像处理显微硬度计安装案例
  • QGY-250型金相试样切割机安装案例
  • HV-1000ASCCT显微图像处理系统案例
  • 安装调试4XCCT金相显微镜图像处理系统
  • 220HBS-3000型数显布氏硬度计安装实例
  • 5公斤小负荷维氏硬度计(带电脑图像分析系
  • P-2G型金相抛光机
  • HVG-30型高端数显维氏硬度计安装实例
  • FR-3e型数显洛氏硬度计
  • 200HRS-150数显洛氏硬度计安装实例
  • 大型250金相切割机的安装调试后,顺利通过
  • HV-1000ASCCT显微图像处理系统案例
  • 4XCCCT金相图像处理显微镜案例
  • 220HBS-3000CCD型图像处理数显布氏硬度
  • MRG-480型研究级金相显微镜图像处理系统
  • 200HVS-10型小符合维氏硬度计图像处理系
  • 图像处理显微硬度计1套,调试安装完成,顺利
  • HBS-3000型精准稳固型数显布氏硬度计顺
  • 系列硬度计安装调试
  • HV-1000ACCT图像处理显微硬度计现场安装
  • HBS-3000型数显布氏硬度计安装实例
  • HV-1000ACCT显微硬度计图像处理系统安装
  • HVS-50型数显维氏硬度计安装实例
  • SQ-80型金相切割机
  • 320HBS-3000型数显布氏硬度计安装实例
  • 客户采购我司提供的金相制样设备,合理地
  • HTS-1000AG型数显里氏硬度计案例
  • 国家文教用品质量监督检验中心-HV-1000
  • 220HBS-3000CCD型图像处理数显布氏硬度
  • HV-1000A(配图像处理系统)显微硬度计案例
  • HV-1000Z型自动转塔显微硬度计
  • MRV-320型孔隙率检测显微镜案例
  • 200HVS-10型小符合维氏硬度计安装顺利完
  • HV-50ASCCT图像处理维氏硬度计安装培训
  • MRG-480型三目倒置金相显微镜图像处理系
  • 4XC型金相显微镜(带电脑及金相分析系统)
  • 联系我们

    莱州市试验机金刚石工具厂

    厂家电话:0535-2215886

    0535-2263683

    0535-2265113

    华东分部:0571-85375562

    外贸联系:13693019205

    行业信息

    当前位置:网站首页 > 新闻资讯 > 行业信息

    • 关于洛氏硬度试验测试及硬度标尺的简要概述
    • 本站编辑:莱州市试验机金刚石工具厂发布日期:2019-10-22 21:04 浏览次数:

    洛氏硬度是以压痕塑性变形深度来确定硬度值的指标,以0.002毫米作为一个硬度单位。在洛氏硬度试验中采用不同的压头和不同的试验力,会产生不同的组合,对应于洛氏硬度不同的标尺。常用的有3个标尺,其应用涵盖了几乎所有常用的金属材料。

    洛氏硬度(HR)测试,当被测样品过小或者布氏硬度(HB)大于450时,就改用洛氏硬度计量。试验方法是用一个顶角为120度的金刚石圆锥体或直径为1.5875mm/3.175mm/ 6.35mm/12.7mm的钢球,在一定载荷下压入被测材料表面,由压痕深度求出材料的硬度。莱州市试验机金刚石工具厂是以机床主轴、回转顶针、丝杠丝杆、轴加工、数控车床加工、刀柄刀杆、夹头接杆为公司的主打产品,品质保障,最常用的三种标尺为A、B、C,即HRA、HRB、HRC,要根据实验材料硬度的不同,选用不同硬度范围的标尺来表示:

    HRA是采用60Kg载荷和钻石锥压入器求得的硬度,用于硬度较高的材料。例如:钢材薄板、硬质合金。

    HRB 是采用100Kg载荷和直径1.5875mm淬硬的钢球求得的硬度,用于硬度较低的材料。例如:软钢、有色金属、退火钢等。

    HRC 是采用150Kg载荷和钻石锥压入器求得的硬度,用于硬度较高的材料。例如:淬火钢、铸铁等。

    硬度标尺:

    洛氏硬度试验采用三种试验力,三种压头,它们共有9种组合,对应于洛氏硬度的9个标尺:HRA、HRB、HRC、HRD、HRE、HRF、HRG、HRH和HRK。这9个标尺的应用涵盖了几乎所有常用的金属材料。

    HRA 60kg载荷金刚石锥压入器;HRB 100kg载荷1/16"直径钢球压头;HRC 150kg载荷金刚石锥压入器;最常用标尺是HRC、HRB和HRF,其中HRC标尺用于测试淬火钢、回火钢、调质钢和部分不锈钢。这是金属加工行业应用最多的硬度试验方法。HRB标尺用于测试各种退火钢、正火钢、软钢、部分不锈钢及较硬的铜合金。HRF标尺用于测试纯铜、较软的铜合金和硬铝合金。HRA标尺尽管也可用于大多数黑色金属,但是实际应用上一般只限于测试硬质合金和薄硬钢带材料。

    表面洛氏硬度试验采用三种试验力,两种压头,它们有6种组合,对应于表面洛氏硬度的6个标尺。表面洛氏硬度试验是对洛氏硬度试验的一种补充,在采用洛氏硬度试验时,当遇到材料较薄,试样较小,表面硬化层较浅或测试表面镀覆层时,就应改用表面洛氏硬度试验。这时采用与洛氏硬度试验相同的压头,采用只有洛氏硬度试验几分之一大小的试验力,就可以在上述试样上得到有效的硬度试验结果。表面洛氏硬度的N标尺适用于类似洛氏硬度的HRC、HRA和HRD测试的材料;T标尺适用于类似洛氏硬度的HRB、HRF和HRG测试的材料。

    洛氏硬度计和表面洛氏硬度计的标尺(即不同的压头和试验力组合)通常按材料种类、试样厚度和硬度范围三方面的因素来选择,具体选择方法叙述如下:

    1、按材料种类选择

    A标尺多用于测量碳化钨、硬质合金、表面硬化零件等等的硬度;

    B标尺多用于测量有色金属、合金及退火钢等低硬度的零件的硬度;

    C标尺多用于测量碳钢、工具钢及合金钢等经淬火、回火处理的试样的硬度。

    按材料选择并不是一种严格的做法。因为每一种材料随着其所采用的不同的热处理工艺,其最终硬度不可能相同,因此所适应的硬度标尺也不会相同。

    2、按样品的硬度范围选择:

    1)样品硬度与材料成分及热处理工艺的关系:在相同的热处理工艺下,材料的含碳量越高,材料的硬度也越高。对应于相同的材料,由工艺引起的硬度高低是:淬火、正火、退火。

    2)各种洛氏硬度标尺的适应范围。每种洛氏硬度标尺都有一个可用范围,这一点很容易从硬度计刻度盘上的分度来确定。

    3、按厚度或硬化层深度

    洛氏硬度试验对样品试样有要求,其厚度不能小于残余压痕深度的10倍,试样背面不能出现明显的变形痕迹。由此样品的厚度决定了载荷的选择,载荷必须保证其所引起的变形小于样品的最小厚度。对于每一种硬度试验,都存在最小可测量厚度。

    测试:

    有一些标尺(如含N、T、W、X、Y的标尺)是对洛氏硬度试验的补充,由表面洛氏硬度试验得出。因为在采用洛氏硬度试验时,当遇到材料较薄,试样较小,表面硬化层较浅或测试表面镀覆层等情况时,就应改用表面洛氏硬度试验。

    之所以分出这么多种标尺,是因为在标尺的使用中,越靠近上下限就越不准。

    HRC标尺的使用范围是20~70HRC,当硬度值小于20HRC时,因为压头的圆锥部分压入太多,灵敏度下降,这时应改用HRB标尺。莱州市试验机金刚石工具厂是以机床主轴、回转顶针、丝杠丝杆、轴加工、数控车床加工、刀柄刀杆、夹头接杆为公司的主打产品,尽管HRC标尺的上限值为70HRC,但是当试样硬度大于67HRC时,压头尖端承受的压力过大,金刚石容易损坏,压头寿命会大大缩短,所以在测量偏HRC标尺上限的硬度时,应使用HRA标尺,因为HRA的上限范围同HRC相当,但试验力要小很多。

    HRA标尺的使用范围是20-88HRA,由美国标准ASTM E140可以获得以下换算关系:27HRA≈30HRB;60HRA≈100HRB≈20HRC;85.6HRA≈68HRC;可见,在同等数值的情况下,对应标尺的硬度由高到低为C、A、B,但HRA标尺的测试范围广,基本包含了HRB和HRC,涵盖了从软钢(HRB)、硬钢(HRC)到硬质合金的硬度范围。

    但事实上,HRA标尺很少用于测试软钢,主要用于测试薄硬钢板、深层渗碳钢和硬质合金。在硬质合金方面,由于技术进步,有些材料硬度已达到93-94HRA,材料硬度超出HRA的测量范围上限已成为惯例。依借于HRA标尺测试范围广的特性,在使用洛氏硬度计测试钢试样时,如果不知试样是软钢还是硬钢,可先用HRA标尺试测一下,当硬度值小于60HRA时可改用HRB标尺,当硬度值大于60HRA时可改用HRC标尺。

    HRB标尺的使用范围是20~100HRB,当硬度值低于20HRB时,由于钢球的压入深度过大,金属蠕变加剧,试样在试验力作用下的变形时间延长,测试值准确度降低,此时应改用HRF标尺。当硬度值大于100HRB时,因为钢球压入深度过浅,灵敏度降低,精度下降,此时应改用HRC标尺。

    在使用HRB标尺测试钢试样时,一个特别值得注意的地方是:当预先不知道试样是软钢还是硬钢时,决不可使用HRB标尺做测试,因为用钢球压头误测了淬火钢,钢球就可能会变形,钢球压头就会损坏,这是钢球压头损坏的主要原因。遇到这种情况时应先用金刚石压头,用HRA标尺测试一下,再决定是用HRB还是用HRC。

    HRF标尺的使用范围是60~100HRF。HRF标尺是国外使用较多的一个标尺,它是测试纯铜和较软的铜合金材料很好的检测手段。但是在中国,也存在标准硬度块短缺的问题,它的应用也受到了限制。

    HRG标尺适用于HRB值接近100的材料,对于铍青铜、磷青铜、可锻铸铁这些硬度范围介于HRB标尺的高端和HRC标尺低端的材料,如果改用HRG标尺,就可以大大改善测试的灵敏度,提高测试精度。

    莱州市试验机金刚石工具厂是以机床顶针、刀柄刀杆、轴加工、CNC数控加工、主轴丝杠、夹头接杆、非标件加工为公司的主打产品,品质保障,值得信赖!

    Rockwell hardness is an index of hardness value determined by the depth of indentation plastic deformation, with 0.002 mm as a hardness unit. Different head and different test force in rockwell hardness test will produce different combinations, corresponding to different scales of rockwell hardness. There are three scales commonly used, and their application covers almost all commonly used metal materials.

    Rockwell hardness (HR) test, when the sample measured is too small or the brinell hardness (HB) is greater than 450, then rockwell hardness measurement is used. The test method is to use a diamond cone with a top Angle of 120 ° or a steel ball with a diameter of 1.5875mm/3.175mm/ 6.35mm/12.7mm to press into the surface of the measured material under a certain load and calculate the hardness of the material from the indentation depth. Laizhou city tester diamond tools factory is A machine tool spindle, rotary plunger, screw, screw, shaft processing, CNC lathe processing, the handle bar, chuck jaw for the company's flagship product, quality guarantee, the most commonly used three kinds of scale as A, B, C, namely, HRA, HRB, HRC, according to the different experimental material hardness, choose different hardness range of scale to indicate:

    HRA is the hardness obtained by using 60Kg load and drill cone presser. It is used for materials with higher hardness. For example: steel sheet, hard alloy.

    HRB is a hardness obtained from a hardened steel ball with a diameter of 1.5875mm and a load of 100Kg. Examples: mild steel, nonferrous metals, annealed steel, etc.

    HRC is the hardness obtained by 150Kg load and drill cone presser. It is used for materials with higher hardness. For example: hardened steel, cast iron and so on.

    Hardness scale:

    Rockwell hardness test USES three test forces and three pressure heads. There are nine combinations corresponding to the nine scales of rockwell hardness: HRA, HRB, HRC, HRD, HRE, HRF, HRG, HRH and HRK. The application of these nine scales covers almost all commonly used metal materials.

    HRA 60kg load diamond cone presser; HRB 100kg load 1/16" diameter steel ball head; HRC 150kg load diamond cone presser; The most commonly used gauges are HRC, HRB, and HRF. HRC gauges are used to test hardened, tempered, tempered, and partially stainless steels. This is the most widely used hardness test method in the metal processing industry. HRB gauge is used to test all kinds of annealed steel, normalizing steel, mild steel, some stainless steel and hard copper alloy. HRF gauge is used for testing pure copper, softer copper alloys and duralumin. Although HRA gauges can also be used for most ferrous metals, their practical applications are generally limited to testing hard and thin steel strip materials.

    The surface rockwell hardness test USES three test forces, two pressure heads, and six combinations corresponding to six scales of surface rockwell hardness. The surface rockwell hardness test is a supplement to the rockwell hardness test. When the rockwell hardness test is used, when the material is thinner, the sample is smaller, the surface hardening layer is shallow or the test surface is coated, the rockwell hardness test should be used instead. A valid hardness test result can be obtained on the sample by using the same head as the rockwell hardness test and a test force that is only a fraction of the size of the rockwell hardness test. The N scale of surface rockwell hardness is applicable to materials tested with HRC, HRA and HRD similar to rockwell hardness. The T scale is suitable for testing materials with HRB, HRF and HRG hardness similar to rockwell hardness.

    The scales of rockwell and surface rockwell durometers (i.e. different combination of head and test force) are usually selected according to the type of material, sample thickness and hardness range. The specific selection method is described as follows:

    1. Choose according to material type

    A scale is mainly used to measure the hardness of tungsten carbide, hard alloy, surface hardened parts and so on.

    B scale is mainly used to measure the hardness of non-ferrous metals, alloys, annealed steel and other low-hardness parts.

    C scale is mainly used to measure the hardness of carbon steel, tool steel and alloy steel after quenching and tempering.

    Selecting by material is not a strict practice. Because each material with its different heat treatment process, its final hardness can not be the same, so adapt to the hardness scale will not be the same.

    2. Choose according to the hardness range of the sample:

    1) relationship between sample hardness and material composition and heat treatment process: under the same heat treatment process, the higher the carbon content of the material, the higher the hardness of the material. Corresponding to the same material, the hardness caused by the process is: quenching, normalizing, annealing.

    2) applicable range of various rockwell hardness scales. Each rockwell hardness scale has a usable range that can be easily determined from the scale on the durometer dial.

    3. According to thickness or depth of hardened layer

    Rockwell hardness test requires that the thickness of the sample should not be less than 10 times of the residual indentation depth, and there should be no obvious deformation traces on the back side of the sample. The thickness of the sample determines the choice of load. The load must be less than the minimum thickness of the sample. For each hardness test, a minimum measurable thickness exists.

    Testing:

    Some scales (such as N, T, W, X, Y) complement the rockwell hardness test and are derived from the surface rockwell hardness test. Because in the use of rockwell hardness test, when the material is thinner, the sample is small, the surface hardening layer is shallow or the test surface coating layer, we should use the surface rockwell hardness test.

    The reason why there are so many kinds of rulers is that in the use of rulers, the closer they are to the upper and lower limits, the less accurate they are.

    The range of use of HRC ruler is 20~70HRC. When the hardness value is less than 20HRC, the sensitivity decreases because the cone part of the head is pressed too much, then HRB ruler should be used. Diamond tools factory laizhou city testing machine is the machine tool spindle, rotary plunger, screw, screw, shaft processing, CNC lathe processing, the handle bar, chuck jaw for the company's flagship product, although the HRC the upper limit of the scale of 70 HRC, but when the sample hardness greater than 67 HRC, head tip pressure is too large, diamond is easy to damage, head will shorten the service life, so in the measurement of partial HRC hardness scale limit, you should use HRA rod, because the limit range with HRC HRA was, but much smaller test force.

    The scope of HRA ruler is 20-88hra, and the following conversion relationship can be obtained from American standard ASTM E140:27HRA≈30HRB; 60 hra material 100 HRB material 20 HRC; 85.6 68 HRC HRA material; It can be seen that, at the same value, the hardness of the corresponding ruler is C, A and B from high to low, but the HRA ruler has A wide test range, basically including HRB and HRC, covering the hardness range from mild steel (HRB) and hard steel (HRC) to hard alloy.

    But in fact, the HRA gauge is rarely used to test mild steel. It is mainly used to test thin and hard steel plate, deep carburized carbon steel and hard alloy. In terms of cemented carbide, due to technological progress, the hardness of some materials has reached 93-94hra, and it has become a convention that the hardness of materials exceeds the upper limit of the measurement range of HRA. According to the characteristics of the wide range of HRA scale test, when using rockwell hardness tester to test steel samples, if you do not know whether the samples are soft steel or hard steel, you can use HRA scale to test first. When the hardness value is less than 60HRA, you can use HRB scale; when the hardness value is greater than 60HRA, you can use HRC scale.

    The range of use of HRB scale is 20~100HRB. When the hardness value is lower than 20HRB, HRF scale should be used instead because the pressing depth of steel ball is too large, the creep of metal is intensified, the deformation time of sample under the action of test force is prolonged, and the accuracy of test value is decreased. When the hardness value is greater than 100HRB, the sensitivity and accuracy of the steel ball will be reduced due to the shallow pressing depth, so HRC scale should be used instead.

    In the use of HRB test steel sample scale, a special note: when don't know in advance sample is soft or hard steel, steel must never use HRB test scale, because with a steel ball head misplaced the hardened steel, steel ball could be out of shape, ball head will be damaged, this is the main reason for the damage of steel ball head. In this case, diamond head should be used first, HRA ruler should be used to test it, and then HRB or HRC should be used.

    The HRF ruler can be used from 60 to 100HRF. HRF ruler is one of the most widely used rulers in foreign countries. It is a good method to test pure copper and soft copper alloy materials. But in China, there is also a shortage of standard blocks, and its use is limited.

    HRG ruler is suitable for materials with HRB value close to 100. Beryllium bronze, phosphorus bronze and malleable iron whose hardness range is between the high end of HRB ruler and the low end of HRC ruler can greatly improve the sensitivity and accuracy of the test if HRG ruler is used instead.

    Laizhou testing machine diamond tool factory is a machine tool thimble, shank, shaft processing, CNC CNC processing, spindle screw, chuck rod, non-standard parts processing as the company's main products, quality assurance, trustworthy!