冷镦钢丝布氏硬度HBW2.5／187.5测量不确定度评定

Uncertainty evaluation of brinell hardness HBW 2.5/187.5 of cold-heading wire

依据GB／T231．1-2009规定的试验方法及其附录C规定的测量不确定度评定方法，对冷镦钢丝布氏硬度HBW2．5／187．5进行测试并评定测量不确定度，分别计算出包含因子为k=2的扩展不确定度为5．8（方法1）和3．9（方法2），相比较，因考虑硬度计带来的不确定度分量不同，方法1可获得较大的扩展不确定度，较可靠，采用附录C规定的方法评定测量不确定度，简化了评定过程，便于操作。

Brinell hardness HBW 2.5/187.5 of cold heading wire was tested and uncertainty was evaluated according to GB/ T 231.1-2009 and its appendix C, It calculate respectively that expanded uncertainty was 5.8 （ method 1 ） and 3.9 （ method 2 ） under the condition of including factor 2, Compare to method2, methodl can obtain more larger uncertainty amt more reliable because of considering the hardness tester of uncertainty components were different, Evaluating the measurement uncertainty by appendix C was concise and easy to operate.