GH4145 bolt Brinell hardness value determination method and apparatus

Abstract

The embodiment of the present invention provides a method and device for determining the Brinell hardness value of GH4145 bolts, the method comprising: obtaining the Leeb hardness values ​​obtained by multiple measurements on each of the multiple parts of at least two sample GH4145 bolts and Brinell hardness value, multiple parts include: thread surface, thread core, polished rod surface and polished rod core; calculate the average Leeb hardness value and average Brinell hardness value of each part; according to the sample GH4145 bolt multiple parts The average Leeb hardness value and the average Brinell hardness value generate a corresponding relationship curve corresponding to each part of the Leeb hardness value and Brinell hardness value; measure the Leeb hardness values ​​of multiple parts of the GH4145 bolt to be tested, according to the corresponding relationship The curve determines the Brinell hardness values ​​of multiple parts of the GH4145 bolt to be tested. This scheme can reduce the deviation that occurs when determining the Brinell hardness value of the GH4145 bolt, reduce the misjudgment rate, and further reduce material waste.

Description

technical field [0001] The invention relates to the technical field of measuring high-alloy steel, in particular to a method and a device for determining the Brinell hardness value of GH4145 bolts. Background technique [0002] GH4145 nickel-based superalloy is an age-hardening deformable superalloy with γ′[Ni3(Al, Ti, Nb)] as the main strengthening phase. It has excellent relaxation resistance, oxidation resistance and high-temperature durability. It is widely used in 300MW , 600MW, or even 1000MW steam turbine cylinder, main valve, flange and other components fastening bolts. Under super (ultra) critical working conditions, the microstructure of GH4145 bolts will undergo changes during service, resulting in a decrease in creep and durability, and an increase in the hardness index on a macro level. Therefore, thermal power plants usually It is to monitor the change of GH4145 bolt performance by measuring Brinell hardness. According to the Electric Power Industry Standard ...

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Problems solved by technology

However, GB / T17394 clearly stipulates that the test objects are low-carbon steel, low-alloy steel and cast steel, while GH4145 bolts are high-alloy steel, so GB / T17394 cannot be directly used for conversion, and GB / T17394 is directly used for testing and conversion. there will be a big error

Therefore, due to the inapplicability of GB / T17394-1998 "Metal Leeb Hardness Test Method" to high-alloy metal parts, whether it is converted according to the attached table of GB / T17394-1998 "Metal Leeb Hardness Test Method" or directly from The Brinell hardness is directly read in the Leeb hardness tester, and the determined Brinell hardness of the GH4145 bolt is bound to have a large deviation, so that in actual work, according to DL / T439-2006 "High Temperature Fastener Technology for Thermal Power Plants" When judging the hardness requirements of GH4145 steel (HBW262-331) in the Guidelines, a serious misjudgment was caused, which resulted in the phenomenon that the actual hardness value was qualified but the test data showed that it was unqualified. For unqualified products, the regulations required remanufacturing. resulting in a huge waste of material

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