Q960 round steel (GB/T 1591) has a composition of 0.10–0.20% carbon (C), 0.20–0.55% silicon (Si), 1.00–1.60% manganese (Mn), 1.50–2.00% chromium (Cr), 0.30–0.80% molybdenum (Mo), 0.02–0.20% niobium (Nb)/titanium (Ti)/vanadyòm (V), mwens pase oswa egal a 0.025% P, mwens pase oswa egal a 0.020% S.
Konpare ak Q890 (0.12-0.20% C, 0.20-0.55% SI, 1.00-1.60% MN, 1.00-2.00% CR, 0.30-0.80% MO, 0.02-0.20% NB/TI), Q960 gen twa ajisteman chimik ki ranfòse fòs rupture: tension:
Pi wo CHROMIUM (1.50-2.00% vs . 1.00 - 2.00%): se minimòm CR kontni an ogmante, fòme plis carbides CHROMIUM (CR₂₃C₆) ki debwatman PIN. Plis karsid vle di pi gwo rezistans nan deformation, dirèkteman ogmante fòs rupture.
Microalloy Optimization: Q960 itilize yon rapò ki pi wo nan niobium Titàn (NB: Ti=3: 1 vs Q890 a 2: 1). NB fòme sibtilite, plis carbides ki estab (NBC) pase TI, ki pi efikas nan revizyon grenn jaden ak debwatman epenglaj - grenn sibtilite ogmante fòs rupture pa limite mouvman debwatman.
Limit ki pi ba (P mwens pase oswa egal a 0.025%, s mwens pase oswa egal a 0.020%vs P Q890 a mwens pase oswa egal a 0.030%, s mwens pase oswa egal a 0.025%): redwi P/s minimize fòmasyon nan konpoze frajil intermetallic (EG, Fe₃p, FE) ki kreye mikwomik. Mwens microcracks vle di asye a ka kenbe tèt ak pi wo charj rupture anvan echèk.
Kontni Kabòn se yon ti kras pi ba (0.10-0.20% vs . 0.12 - 0.20%) pou fè pou evite fragilite, kòm Q960 depann sou sinèrji alyaj olye ke kabòn reyalize ultra - segondè fòs.