Blog

Per GB/T 197, tolerance band = grade + fundamental deviation. External 6g and internal 6H form the default medium fit; learn basic sizes per GB/T 196 and g

Torque-angle controls bolt elongation by seat torque plus a turned angle (scatter ±15-20%); yield-point stops just past yield (scatter ±8-10%). Compare the

Tightening torque T=K·F·d: ~50% bearing friction, ~40% thread friction, only ~10% becomes preload. Learn why K scatters ±25-40% and how to use torque metho

Decode ISO 3506/GB/T 3098.6 stainless codes: A2 approx 304, A4 approx 316 Mo-bearing; dash figure = 1/10 tensile. Compare strength, corrosion, galling prev

Decode GB/T 3098.1 property-class codes: left figure=1/100 tensile, right=10x yield ratio. Compare 8.8/10.9/12.9 strength, Q&T requirements, head marks and

Cold heading vs CNC is a volume and geometry decision. Compare batch threshold, material utilization, cycle, strength and upsetting/extrusion limits with a

A 6061 lifting sleeve cut from pure CNC (RMB50, 20min) to cold-headed blank plus minimal machining (RMB20, 4min), 5x output, stronger continuous grain flow

VDA 19.2 extends cleanliness to the assembly flow. Learn gravimetric vs particle counting vs SEM EDAX, blank-value and attenuation tests, five-stage wash a

Technical cleanliness has become a key characteristic on a par with strength. Learn pollutant sources, failure mechanisms, ISO 16232 vs VDA 19 and three cl

ZT68 600MPa cold-headed aluminum bolts save 65% vs steel while matching Mg/Al in potential and thermal expansion. See the weight calculus across NEV three-