Effect of tempering temperature on precipitate evolution and mechanical properties of 34CrNiMo6 steel

Abstract Steels with martensitic and tempered martensitic microstructures, though sometimes perceived as brittle, exhibit plasticity and ductile fracture behavior under certain conditions. This chapter describes the alloying and tempering conditions that produce a ductile form of martensite in low-carbon steels. It also discusses the effect of tempering temperature on the mechanical behavior and deformation properties of medium-carbon steels.

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Microstructure and Mechanical Properties of 34CrNiMo6 Steel Repaired by Friction Stir Processing

Materials ◽

10.3390/ma12020279 ◽

2019 ◽

Vol 12 (2) ◽

pp. 279 ◽

Cited By ~ 2

Author(s):

Zhongwen Wu ◽

Chunping Huang ◽

Fencheng Liu ◽

Chun Xia ◽

Liming Ke

Keyword(s):

Mechanical Properties ◽

Friction Stir Processing ◽

Steel Structures ◽

Optical Microscope ◽

Filling Material ◽

Welding Wire ◽

Friction Stir ◽

Filling Materials ◽

Microstructure And Mechanical Properties ◽

34Crnimo6 Steel

Repairing damaged parts using proper repairing methods has become an important means to reduce manufacturing and operational costs and prolong the service life of 34CrNiMo6 steel structures. In the conventional fusion repairing method, welding wire and powder are often used as filling materials. Filling materials are often expensive or difficult to find. Some metallurgical issues (such as solidification crack, higher distortion) were also found with these methods. At the same time, most of the equipment that requires welding wire and powder is expensive. In this study, a new method based on friction stir processing (FSP) was successfully employed to repair 34CrNiMo6 steel, using a block as filling material. Filling blocks are much cheaper than conventional fusion repair consumables. As a result of solid-state repair, this method can also avoid the metallurgical issues of fusion repair. The microstructure and mechanical properties of the repaired samples were investigated using OM (Optical Microscope), SEM, EDS (Energy Dispersive Spectroscopy), XRD, and a Vickers hardness electronic universal tensile tester. The results showed that 34CrNiMo6 steel was successfully repaired by this method, with no defect. Tensile tests showed that the maximum ultimate strength (UTS) was 900 MPa and could reach 91.8% of that of the substrate. The fracture mode of the tensile samples was ductile/brittle mixed fracture. Hence, the repairing method based on FSP appears to be a promising method for repairing castings.

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Effects of Silicon Content and Tempering Temperature on the Microstructural Evolution and Mechanical Properties of HT-9 Steels

Materials ◽

10.3390/ma13040972 ◽

2020 ◽

Vol 13 (4) ◽

pp. 972 ◽

Cited By ~ 1

Author(s):

Junkai Liu ◽

Wenbo Liu ◽

Zhe Hao ◽

Tiantian Shi ◽

Long Kang ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Microstructural Evolution ◽

Charpy Impact ◽

Hardness Test ◽

Mechanical Tests ◽

Fourth Generation ◽

Martensitic Steels ◽

Microscopic Mechanism ◽

Tempering Temperature

Two kinds of experimental ferritic/martensitic steels (HT-9) with different Si contents were designed for the fourth-generation advanced nuclear reactor cladding material. The effects of Si content and tempering temperature on microstructural evolution and mechanical properties of these HT-9 steel were studied. The microstructure of experimental steels after quenching and tempering were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM); the mechanical properties were investigated by means of tensile test, Charpy impact test, and hardness test. The microscopic mechanism of how the microstructural evolution influences mechanical properties was also discussed. Both XRD and TEM results showed that no residual austenite was detected after heat treatment. The results of mechanical tests showed that the yield strength, tensile strength, and plasticity of the experimental steels with 0.42% (% in mass) Si are higher than that with 0.19% Si, whereas hardness and toughness did not change much; when tempered at 760 °C, the strength and hardness of the experimental steels decreased slightly compared with those tempered at 710 °C, whereas plasticity and toughness increased. Further analysis showed that after quenching at 1050 °C for 1 h and tempering at 760 °C for 1.5 h, the comprehensive mechanical properties of the 0.42% Si experimental steel are the best compared with other experimental steels.

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Microstructure and Mechanical Properties of High Strength Alloyed Steel for Aerospace Application

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.284.351 ◽

2018 ◽

Vol 284 ◽

pp. 351-356 ◽

Cited By ~ 1

Author(s):

Mikhail V. Maisuradze ◽

Maksim A. Ryzhkov

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

High Strength ◽

Single Stage ◽

The Novel ◽

Tempering Temperature ◽

Quenching And Partitioning ◽

Aerospace Application ◽

Cooling Conditions ◽

Quenching And Tempering

The high strength aerospace steel alloyed with Cr, Mn, Si, Ni, W and Mo was studied. The austenite transformations under continuous cooling conditions were investigated using the dilatometer analysis at the cooling rates 0.1...30 °C/s. The mechanical properties of the studied steel were determined after the conventional quenching and tempering heat treatment. The dependences of the mechanical properties on the tempering temperature were obtained. The novel quenching and partitioning heat treatment was applied to the steel under consideration. The microstructure and the mechanical properties were studied after three different modes of the quenching and partitioning (QP) treatment: single-stage QP, two-stage QP and single-stage QP with subsequent tempering (QPT).

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Effect of Tempering Temperature on Microstrueture and Mechanical Properties of Steel Containing Ni of 9 %

Journal of Iron and Steel Research International ◽

10.1016/s1006-706x(11)60064-2 ◽

2011 ◽

Vol 18 (5) ◽

pp. 47-51 ◽

Cited By ~ 19

Author(s):

Xi-qing Zhao ◽

Tao Pan ◽

Qing-feng Wang ◽

Hang Su ◽

Cai-fu Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Tempering Temperature

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Influence of Martensite Deformation on Cu Precipitation Strengthening

Metals ◽

10.3390/met10020282 ◽

2020 ◽

Vol 10 (2) ◽

pp. 282

Author(s):

Jaromir Dlouhy ◽

Pavel Podany ◽

Ján ǅugan

Keyword(s):

Mechanical Properties ◽

Yield Strength ◽

Cold Rolling ◽

Temperature Dependence ◽

Precipitation Hardening ◽

Precipitation Strengthening ◽

Tempering Temperature ◽

Quenching And Tempering

Cu precipitation strengthening was compared in steels after treatments with and without cold rolling. A 0.2% C steel containing up to 1.5% Cu was quenched and tempered. Cu precipitation took place during tempering and increased its yield strength (YS). Quenched and tempered samples were compared with samples where cold rolling was performed between quenching and tempering. They exhibited significantly different mechanical properties. In addition, Cu alloying influenced the properties of each group of samples in different ways. The quenched and tempered samples exhibited behavior that is typical of precipitation hardening. Cu caused yield strength to increase with tempering temperature and time. The cold rolling of martensite reduced the maximal Cu-related strengthening and also eliminated its time and temperature dependence.

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Effect of Tempering Temperature on the Structure and Mechanical Properties of Steel 38KhM in the Case of Nonthrough Hardening

Metal Science and Heat Treatment ◽

10.1007/s11041-018-0296-0 ◽

2018 ◽

Vol 60 (7-8) ◽

pp. 433-438

Author(s):

A. A. Khlybov ◽

R. A. Vorob’ev ◽

V. N. Dubinskii

Keyword(s):

Mechanical Properties ◽

Tempering Temperature

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Optimalization of Tempering Temperature of 9CrNB Steel in Železiarne Podbrezová Steelworks

Materials Science Forum ◽

10.4028/www.scientific.net/msf.891.137 ◽

2017 ◽

Vol 891 ◽

pp. 137-142 ◽

Cited By ~ 1

Author(s):

Ľudovít Parilák ◽

Pavel Bekeč ◽

Lucia Domovcová ◽

Pavol Beraxa ◽

Milan Mojžiš ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Microstructural Analysis ◽

Theoretical Studies ◽

Secondary Phases ◽

Tempering Temperature ◽

Carbide Phases ◽

Hot Rolled ◽

Martensite Microstructure ◽

Very High

This paper deals with the optimalization of tempering temperature of 9CrNB steel in Železiarne Podbrezová Steelworks, where hot-rolled tubes were produced with dimensions of 88.9 x 12.51 mm. Austenitising at 1070°C/12m/hr was carried out after rolling, and samples were subsequently tempered at 790°C, 760°C and 720°C/4m/hr. The results of testing the mechanical properties show that only tempering at 790°C fulfilled all of the mechanical properties requirements (Rp0,2, Rm, A5, HBW, KV2). The mechanical properties of grade P92 were used for comparison with 9CrNB mechanical properties, according to the relevant standard of STN EN 10216-2+A2. Yield strength requirements (Rp0,2) were also fulfilled in the temperature range from 100 to 600 °C. Microstructural analysis showed that tempering at 720°C, and also at 760°C does not lead to the complete tempering of martensite microstructure. We observed segregation of secondary phases at the grain boundary, but cementite films between individual laths did not coagulate to form carbide phases. By tempering at 790°C the intensity of formation of carbide phases, coagulation and growth of carbide phases is very high and leads to disintegration of laths. Despite satisfactory results, theoretical studies with respect to the selected chemical composition of 9CrNB steel show that to achieve sufficient dissolution of carbide or nitride phases (especially BN), it is necessary to use high temperature austenitization up to about 1200°C, followed by tempering below Ac1.

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