C90油管钢的氢损伤

对比研究了三种油管钢（宝钢的Ｃ９０和日本的ＳＭ９０及ＳＭ９５）的氢致开裂性能．ＳＭ９０，ＳＭ９５和Ｃ９０产生氢损伤的临界扩散氢质量分数（×１０~（－６））分别为１．７６，４．３和８．３８；临界全氢质量分数（×１０~（－６））分别为４．２４，６．３５和１０．２２三种钢在Ｈ_２Ｓ中的门槛应力σ_（ｔｈ）／σ_ｓ分别为０．６４，０．８０和０．８５．三种油管钢抗氢损伤能力和抗氢致滞后断裂的能力是一致的，以Ｃ９０为最好，它和氢的扩散系数无关．Ｃ９０钢缺口试样氢致滞后断裂门槛值Ｋ_（ＩＨ）与可扩散的氢质量分数ｗ_０有关，实验获得Ｋ_（ＩＨ）＝４６－１２．５１ｌｎ_（ｗ０）．理论分析和实验结果完全一致．对Ｃ９０钢，当ｗ_０≤４．８×１０－６时，在任何Ｋ_Ｉ／Ｋ_Ｃ下均将获得韧窝断口；ｗ_０≥７．６×１０~（－６），Ｋ_Ｉ／Ｋ_Ｃ≥０．５时，则氢致韧断；Ｋ_Ｉ／Ｋ_Ｃ≤０．４时，则氢致脆断．     

油井管钢氢致开裂门槛值研究

四种高强度油井管钢动态及氢时,进入试样的可扩散氢含量ｃ０和充氢电流ｉ成正比,而氢致断裂门榄应力σｃ与名义屈服强度σｔ之比和ｌｎｃ０成正比,即σｃ／σｔ＝Ａ－Ｂｌｎｃ０,测量了四种钢在Ｈ２Ｓ中浸泡进入试样的Ｃ０,求出相应的ｉｃ,用ｉｃ充氢时同的门槛应力σｃ（Ｈ）／σｔ和Ｈ２Ｓ中应力腐蚀门槛应力σＣ（Ｈ２Ｓ）／σｔ相一致,这表明,可用特定电流下的动态充氢来代替Ｈ２Ｓ应力腐蚀。     

Mechanism of hydrogen-induced intergranular cracking of tubular steels

Hydrogen could be enriched on grain boundaries by stress induction and other traps.The enriched hydrogen facilitated emission and movement of dislocations and lowered plastic work.Consequently,fracture occurred easily along grain boundary.A normalized threshold value of hydrogen-induced cracking (HIC) along grain boundary is given as (KIH/KIC)2=1-0.162×10-3 βHCc(H)GH/(2γs-γb-0.16×103∑β CiGi),where βH and βi are the enrichment factors of hydrogen and other elements on grain boundaries,respectively;Cc(H) is hydrogen concentration induced by stress;C,is the average concentration of an element in the steel;GH and Gi are factors of fracture work along grain boundary with hydrogen and other elements,and γs and γb are surface free energy and grain boundary energy of Fe.For tubular steel,the calculated KH/KIC is 0.23 while the determined value is 0.26.The theoretical threshold value is well consistent with the experimental one.     

夹杂,晶界和缺口前端的氢富集

用离子探针研究了２８ＣｒＭｏＴｉＢ油管钢中氢在夹杂，晶界和缺口前端的富集。结果表明，在ＴｉＮ，ＡｌＯ３，ＴｉＯ，ＭｎＳ以及复合氧化物夹杂界面的氢富集分别为１０－２０，８－１４，１０，１０－１７以及１３－１４，氢在表面和晶界的富集分别为１．２和７．３在加载缺口前端存在两个氢富集峰，氢富集为２．５－４．５。