1 Shanghai Hailong Oil Tubular Goods Research Institute, Shanghai 200949, China 2 Hilong Group of Companies Ltd., Shanghai 200949, China
Cite this article:
Zhiqiang SHU,Pengbin YUAN,Zhiying OUYANG,Danmei GONG,Xueming BAI. Effects of Tempering Temperature on Microstructure and Mechanical Properties of Drill Pipe Steel 26CrMo. Acta Metall Sin, 2017, 53(6): 669-676.
The effects of tempering temperature on microstructure and mechanical properties of steel 26CrMo were studied based on mechanical property tests and microstructure observation. The results show that a phase matrix gradually occurs recovery and recrystallization with increasing temperature during 540~690 ℃ temper process, martensite morphology fades away gradually, flake or rocklike carbides separate out along the martensite boundaries, and then change into granulated dispersed distribution, at 690 ℃ tempering carbides happen aggregation and growth on grain boundaries. With tempering temperature increasing, the strength of 26CrMo steel is gradually reducing, plasticity and toughness are gradually increasing. The tensile property and impact energy can meet all different grade drill pipe requirements in API 5DP standard with different tempering conditions. The total impact energy, crack initiation energy and crack propagation energy of 26CrMo steel are gradually increasing with the tempering temperature rising, the crack propagation energy is three times of crack initiation energy which shows great anti-crack propagation capability, but their ratio has no obvious change. The change of impact pro-perty is closely related to the strength and plasticity change, impact toughness stand or fall depends on high or low plasticity.
Fig.3 Effects of tempering temperature on tensile strength Rm, yield strength Rp and elongation A of 26CrMo steel
Fig.4 Effects of tempering temperature on strain hardening exponent n and uniform deformation capacity Up of 26CrMo steel
Fig.5 Effect of tempering temperature on yield ratio of 26CrMo steel
Fig.6 Impact force and deflection curves of 26CrMo steel tempered at different temperatures after instrumented Charpy impact test at room temperature (Fm—maximum impact force, Sm—displacement of maximum impact force, St—total impact displacement)
Fig.7 Effects of tempering temperature on total impact energy Wt , crack initiation energy Wi and crack propagation energy Wp of 26CrMo steel
Fig.8 Low (a, c, e, g, i) and high (b, d, f, h, j) magnified SEM fractographs of 26CrMo steel tempered at 540 ℃ (a, b), 595 ℃ (c, d), 620 ℃ (e, f), 655 ℃ (g, h) and 690 ℃ (i, j) after impact test at room temperature
Fig.9 SEM images of 26CrMo steel tempered at 540 ℃ (a), 595 ℃ (b), 620 ℃ (c), 655 ℃ (d) and 690 ℃ (e)
Fig.10 Effects of tempering temperature on Rm and Fm of 26CrMo steel
Fig.11 Effects of tempering temperature on n and Sm of 26CrMo steel
[1]
Liu X S.Drilling Technology Principle [M]. Beijing: Petroleum Industry Press, 1988: 95
[1]
(刘希圣. 钻井工艺原理 [M]. 北京: 石油工业出版社, 1988: 95)
[2]
Long Z H, Zhang J H.Drilling Engineering [M]. Beijing: China Petrochemical Press, 2010: 64
[2]
(龙芝辉, 张锦宏. 钻井工程[M]. 北京: 中国石化出版社, 2010: 64)
[3]
Gao L X, Zhang Y.String Design and Oil Tubular Goods Selection [M]. Beijing: Petroleum Industry Press, 2013: 97
[3]
(高连新, 张毅. 管柱设计与油井管选材 [M]. 北京: 石油工业出版社, 2013: 97)
[4]
Zhang Y, Zhao R C, Zhang R X.Comment on technical quality of high-strength drill pipes made at home and abroad[J]. Steel Pipe, 2000, 29(5): 1
Wang X H, Zhang G J, Li F P, et al.Chemical composition, heat treatment and mechanical properties of drill pipe steel[J]. Petrol. Tub. Goods Instrum., 2015, 1(2): 33
Zhang Z P, Zhang J S, Ning B Q.Effects of tempering temperature on microstructure and mechanical properties of 28CrMo47V steel[J]. Hot Work. Technol., 2012, 41(18): 184
Shaeri M H, Saghafian H, Shabestari S G.Effects of austempering and martempering processes on amount of retained austenite in Cr-Mo steels (FMU-226) used in mill liner[J]. J. Iron Steel Res. Int., 2010, 17: 53
[12]
Huang B S, Jiang Z Y, Pan H H, et al.Influence of different heat treatment on corrosion resistance of G105 pipe[J]. J. Chin. Soc. Corros. Protect., 2012, 32: 67
Ouyang Z Y, Shu Z Q, Yuan P B.Effect of yield ratio on the performance of high strength and high ductility drill pipe[J]. Phys. Test. Chem. Anal.(Phys. Test.), 2013, 49A: 17
Gao H L.Analysis and commentary on yield ratio of pipeline steel[J]. Welded Pipe Tube, 2010, 33(6): 10
[15]
(高惠临. 管线钢屈强比分析与评述[J]. 焊管, 2010, 33(6): 10)
[16]
Tang Z T.Relationship between fracture and force-displacement curve of impact specimen[J]. Phys. Exam. Test., 2004, (4): 1
[16]
(唐振廷. 冲击试样断口与力-位移曲线之间的关系[J]. 物理测试, 2004, (4): 1)
[17]
Wang H, Han L H, Hu F, et al.Effect of tempering temperature on precipitate and mechanical properties of an anti-sulfur, drill pipe steel in H2S containing environments[J]. Trans. Mater. Heat Treat., 2012, 33(3): 88
Hui W J, Dong H, Weng Y Q, et al.Effect of heat treatment para-meters on mechanical properties of high strength Cr-Mo-V steel[J]. Acta Metall. Sin., 2002, 38: 1009
Qin B, Wang Z Y, Sun Q S.Effect of tempering temperature on properties of 00Cr16Ni5Mo stainless steel[J]. Mater. Charact., 2008, 59: 1096
[21]
Wen T, Hu X F, Song Y Y, et al.Effect of tempering temperature on carbide and mechanical properties in a Fe-Cr-Ni-Mo high-strength steel[J]. Acta Metall. Sin., 2014, 50: 447
Yuan S P, Liu G, Wang R H, et al.Coupling effect of multiple precipitates on the ductile fracture of aged Al-Mg-Si alloys[J]. Scr. Mater., 2007, 57: 865
[26]
Zhou H J, Tu M J, Deng Z J, et al.On the development of strength potentialities of metallic materials, the second part——Rational balance between strength and ductility or toughness[J]. J. Xi′an Jiaotong Univ., 1980, 14(1): 25
