... Material: 25Mnv, 20Mn2, Q235 2.Finish: blackened, zinc-plated, HDG 3.Size: 4mm-32mm alloy steel chains Introduction:We are specialized ... , black oxide, electro galvanized, hot dip galvanized, black painted etc.3) Material: 20Mn2, 25Mnv, Q235 (alloy steel chains, mild steel chains ... and Welding 9.Check surface 10. Sampling and breaking test 11.Calibration 12. Heat treatment 13. Proof load test 14. Black ...