Reference link: https: //mp.weixin.qq.com/s/7-HOJi3AkXBrU_gVREDp8Q
A basic concept:
1. Brinell hardness (HB)
A constant load (typically 3000kg) to a certain size (diameter typically 10mm) hardened steel ball pressed into the surface of the material, for a time after removal of a load, the ratio of load area of its indentation, is the Brinell hardness ( HB), in units of kgf / mm2 (N / mm2).
2. Rockwell hardness (HR)
When h HB> 450 or through the sample, and can not be used to switch Brinell hardness test Rockwell hardness measurement. It is a diamond cone apex angle of 120 ° or 1.59,3.18mm ball diameter, and in certain load onto the surface of the test material, the hardness of the material is determined by the depth of the indentation. Depending on the hardness of the test material, in three different scale represented:
· HRA: 60kg load and the hardness is the use of diamond is pressed into the cone obtained, a very high hardness material (such as carbide, etc.) is used.
· HRB: 100kg load, and is using 1.58mm diameter hardened steel ball, the hardness obtained, for low hardness material (such as annealed steel, cast iron, etc.).
· HRC: hardness is the use of diamond cone and a 150kg load obtained is pressed into, for high hardness material (such as hardened steel, etc.).
3 Vickers hardness (HV)
And a load of 120kg for the apex angle less than 136 ° diamond pyramid indenter into the square is pressed into the surface of the material, by dividing the indentation load value pit surface area material, i.e. the value of the Vickers hardness HV (kgf / mm2).
Brinell hardness and a strong relationship between the degree of
Hardness testing methods
Second, the relationship between the hardness and strength:
Practice has proved that among various hardness values of metal material, has an approximately corresponding relationship between hardness and strength values. Since hardness value is determined by the start of plastic deformation resistance and plastic deformation resistance continues, the higher the strength of the material, the higher the plastic deformation resistance, the higher the hardness value. But not consistent in terms of the relationship of various materials.
The difference between strength and hardness: strength reliability is emphasized, that can not fail. Hardness is emphasized and invasion ability of anti-intrusion, such as jigs pad, the jig sets, as well as cutting tools.
III., And table conversion formula
Conversion formula
Hardness table:
The German standard DIN50150, the following is a common range of tensile strength and Vickers hardness of the steel, Brinell hardness, Rockwell hardness table.
|
|
Vickers hardness |
Brinell hardness |
Rockwell hardness |
| 250 |
80 |
76.0 |
- |
| 270 |
85 |
80.7 |
- |
| 285 |
90 |
85.2 |
- |
| 305 |
95 |
90.2 |
- |
| 320 |
100 |
95.0 |
- |
| 335 |
105 |
99.8 |
- |
| 350 |
110 |
105 |
- |
| 370 |
115 |
109 |
- |
| 380 |
120 |
114 |
- |
| 400 |
125 |
119 |
- |
| 415 |
130 |
124 |
- |
| 430 |
135 |
128 |
- |
| 450 |
140 |
133 |
- |
| 465 |
145 |
138 |
- |
| 480 |
150 |
143 |
- |
| 490 |
155 |
147 |
- |
| 510 |
160 |
152 |
- |
| 530 |
165 |
156 |
- |
| 545 |
170 |
162 |
- |
| 560 |
175 |
166 |
- |
| 575 |
180 |
171 |
- |
| 595 |
185 |
176 |
- |
| 610 |
190 |
181 |
- |
| 625 |
195 |
185 |
- |
| 640 |
200 |
190 |
- |
| 660 |
205 |
195 |
- |
| 675 |
210 |
199 |
- |
| 690 |
215 |
204 |
- |
| 705 |
220 |
209 |
- |
| 720 |
225 |
214 |
- |
| 740 |
230 |
219 |
- |
| 755 |
235 |
223 |
- |
| 770 |
240 |
228 |
20.3 |
| 785 |
245 |
233 |
21.3 |
| 800 |
250 |
238 |
22.2 |
| 820 |
255 |
242 |
23.1 |
| 835 |
260 |
247 |
24.0 |
| 850 |
265 |
252 |
24.8 |
| 865 |
270 |
257 |
25.6 |
| 880 |
275 |
261 |
26.4 |
| 900 |
280 |
266 |
27.1 |
| 915 |
285 |
271 |
27.8 |
| 930 |
290 |
276 |
28.5 |
| 950 |
295 |
280 |
29.2 |
| 965 |
300 |
285 |
29.8 |
| 995 |
310 |
295 |
31.0 |
| 1030 |
320 |
304 |
32.2 |
| 1060 |
330 |
314 |
33.3 |
| 1095 |
340 |
323 |
34.4 |
| 1125 |
350 |
333 |
35.5 |
| 1115 |
360 |
342 |
36.6 |
| 1190 |
370 |
352 |
37.7 |
| 1220 |
380 |
361 |
38.8 |
| 1255 |
390 |
371 |
39.8 |
| 1290 |
400 |
380 |
40.8 |
| 1320 |
410 |
390 |
41.8 |
| 1350 |
420 |
399 |
42.7 |
| 1385 |
430 |
409 |
43.6 |
| 1420 |
440 |
418 |
44.5 |
| 1455 |
450 |
428 |
45.3 |
| 1485 |
460 |
437 |
46.1 |
| 1520 |
470 |
447 |
46.9 |
| 1555 |
480 |
(456) |
47.7 |
| 1595 |
490 |
(466) |
48.4 |
| 1630 |
500 |
(475) |
49.1 |
| 1665 |
510 |
(485) |
49.8 |
| 1700 |
520 |
(494) |
50.5 |
| 1740 |
530 |
(504) |
51.1 |
| 1775 |
540 |
(513) |
51.7 |
| 1810 |
550 |
(523) |
52.3 |
| 1845 |
560 |
(532) |
53.0 |
| 1880 |
570 |
(542) |
53.6 |
| 1920 |
580 |
(551) |
54.1 |
| 1955 |
590 |
(561) |
54.7 |
| 1995 |
600 |
(570) |
55.2 |
| 2030 |
610 |
(580) |
55.7 |
| 2070 |
620 |
(589) |
56.3 |
| 2105 |
630 |
(599) |
56.8 |
| 2145 |
640 |
(608) |
57.3 |
| 2180 |
650 |
(618) |
57.8 |
| 660 |
58.3 |
||
| 670 |
58.8 |
||
| 680 |
59.2 |
||
| 690 |
59.7 |
||
| 700 |
60.1 |
||
| 720 |
61.0 |
||
| 740 |
61.8 |
||
| 760 |
62.5 |
||
| 780 |
63.3 |
||
| 800 |
64.0 |
||
| 820 |
64.7 |
||
| 840 |
65.3 |
||
| 860 |
65.9 |
||
| 880 |
66.4 |
||
| 900 |
67.0 |
||
| 920 |
67.5 |
||
| 940 |
68.0
|
三. 关于洛氏硬度的详细介绍
洛氏硬度试验是现今所使用的几种普通压痕硬度试验之一，三种标尺的初始压力均为98.07N(合10kgf)，最后根据压痕深度计算硬度值。标尺A使用的是球锥菱形压头，然后加压至588.4N(合60kgf)；标尺B使用的是直径为1.588mm(1/16英寸)的钢球作为压头，然后加压至980.7N(合100kgf)；而标尺C使用与标尺A相同的球锥菱形作为压头，但加压后的力是1471N(合150kgf)。因此标尺B适用相对较软的材料，而标尺C适用较硬的材料。
参考链接：https://mp.weixin.qq.com/s/E1qkhUgTtnYTPrHm4Im_Kg
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。
1、测试结果不同：
HRA：是采用60kg载荷和钻石锥压入器求得的硬度，用于硬度极高的材料(如硬质合金等)。
HRB：是采用100kg载荷和直径1.58mm淬硬的钢球，求得的硬度，用于硬度较低的材料(如退火钢、铸铁等)。
HRC：是采用150kg载荷和钻石锥压入器求得的硬度，用于硬度很高的材料(如淬火钢等)。
2、换算不同：HRB100 = HRC20；HRB99.2＝HV226=HRC20.0；HRB96＝HV211=HRC17.0。
3、 洛氏硬度试验是现今所使用的几种普通压痕硬度试验之一，三种标尺的初始压力均为98.07N(合10kgf)，最后根据压痕深度计算硬度值。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。