LT ——Inspection standard of key procedure for high- strength heat-treated anchor bolt


1.1 Heat-treatment procedure inspection refers to tests on steel round bars, in the duration of heat treatment production line, which, mechanical properties, hardness, impact absorb energy at low temperature tests are the mainly part.

3.2 Sampling: according to Table 3


Table 3 Heat-treatment procedure inspection 

Grade Rm/Mpa Rp0.2/Mpa A% Z% -40℃Akv2/J Hardness Height of partial-decarburization on threads  Depth of complete decarburization on threads  Decarburization of roots mm Grain size晶粒度级别 Metallographic structure金相组织
10.9 ≥1040 ≥940 ≥9 ≥48 ≥50 HRC 32-39 2/3H1 ≤0.015mm Shall be free of complete decarburization, depth of partial decarburization≤0.050mm ≥9.5 Tempered sorbite回火索氏体
8.8 ≥830 ≥660 ≥12 ≥52 ≥70 HRC 23-34 1/2H1 ≤0.015mm Shall be free of complete decarburization, depth of partial decarburization≤0.050mm ≥9.5 tempered sorbite+few ferrit 回火索氏体+少量铁素体
sampling 1/bundle 1/bundle 1/bundle 1/bundle 1/bundle 2/shift 1/shift 1/shift 1/shift 1个/heat炉 1个/heat炉


If heat-treatment procedure inspection fail during production, main control program must be adjusted according to Table 3 requirements, after which, production continues.


3.3 Table 3 above is only apply to high-strength anchor bolt of grade 8.8 and 10.9. If other grade specified, inspection requirements accotding to “Production notification” 

3.4  Relative documents: “Test records of products”, “Test records of impact energy”, “Heat-treated materials——Test records of hardness”, “Heat-treated materials——Test records of decarburization on threads”, “Heat-treated materials——Test records of grain size”, “Disposal records of unqualified materials” 

3.5 Measuring instruments: : hydraulic servo tensile testing machine, semi-automatic impact tester, low temperature instrument, rockwell hardness tester,   metalloscope. 

3.6 Reference standard:GB/T3098.1、GB/T228.1 、Q/GW-206066-2016 、GB/T229 、GB/T230.1 、GB/T6394


Our manufacture have the most advanced facility of heat treatment, with experienced experts and service teams. Main products are Wind turbine foundation cage, anchor bolts, studs, nuts, washers, rock bolts, heat treating round bars, heat treated stirrup, seamless tubes.


Anyang Longteng Heat Treatment Material Co.,Ltd

Add:  Industrial Park, Indu District, Anyang City, Henan Province, P.R.C.

TEL:  +86-372-2256782

Email: [email protected]




Post time: Aug-29-2018