Abstract: During the quality monitoring process in finished bolt materials product acceptance, significant deviations often occur in Leeb hardness test results. Using laboratory-simulated field testing methods, Leeb hardness tests were conducted on finished nuts and large pipe fittings. The study analyzed the influence of factors such as sample mass and thickness, surface condition, test location, and metal material on the test results. The results show that when using a Leeb hardness tester for field testing, samples that did not meet standard mass requirements must be coupled with an appropriate support body before testing. Errors in Leeb hardness testing could be reduced by changing the test direction of the sample, decreasing surface roughness, or selecting an appropriate test location. The test results were significantly affected by the elastic deformation of the material.