Study on methods to improve the impact toughness of steel 40XA

Author(s):  
Duong Nguyen Van ◽  
◽  
Quy Pham Van

In this paper, methods of improving the toughness, eliminating the tempering embrittlement of steel 40XA (GOST 4543 -71) were used. The mechanical properties of this steel after conventional oil quenching followed by high temperature tempering with air cooling and with oil cooling after high temperature tempering were investigat- ed. Besides, a double quenching process consisting of a preliminary quenching from high temperature and a sec- ondary quenching with intermediate holding at sub-critical temperature was conducted. After this double quench- ing and high temperature tempering, the steel acquired mechanical properties (tensile strength, elongation and impact toughness) notably higher than the respective properties obtained by conventional heat treating. These research results can be applied to improve the mechanical properties of important details from this steel.

2019 ◽  
Vol 9 (20) ◽  
pp. 4231
Author(s):  
Oskari Haiko ◽  
Antti Kaijalainen ◽  
Sakari Pallaspuro ◽  
Jaakko Hannula ◽  
David Porter ◽  
...  

In this paper, the effects of different tempering temperatures on a recently developed ultrahigh-strength steel with 0.4 wt.% carbon content were studied. The steel is designed to be used in press-hardening for different wear applications, which require high surface hardness (650 HV/58 HRC). Hot-rolled steel sheet from a hot strip mill was austenitized, water quenched and subjected to 2-h tempering at different temperatures ranging from 150 °C to 400 °C. Mechanical properties, microstructure, dislocation densities, and fracture surfaces of the steels were characterized. Tensile strength greater than 2200 MPa and hardness above 650 HV/58 HRC were measured for the as-quenched variant. Tempering decreased the tensile strength and hardness, but yield strength increased with low-temperature tempering (150 °C and 200 °C). Charpy-V impact toughness improved with low-temperature tempering, but tempered martensite embrittlement at 300 °C and 400 °C decreased the impact toughness at −40 °C. Dislocation densities as estimated using X-ray diffraction showed a linear decrease with increasing tempering temperature. Retained austenite was present in the water quenched and low-temperature tempered samples, but no retained austenite was found in samples subjected to tempering at 300 °C or higher. The substantial changes in the microstructure of the steels caused by the tempering are discussed.


Author(s):  
Sijing Fu ◽  
Binghua Jiang ◽  
Jing Wang ◽  
Hong Cheng

In this paper, near net shape casting technology was used to manufacture Cr12MoV steel die modified using RE-Ti. The samples with different RE(rare earth)-Ti content were fabricated by using the induction furnace. The microstructure of the samples was analyzed by using optical microscope and scanning electron microscope. Electronic universal tensile test machine, pendulum impact tester and rockwell apparatus were utilized to test the mechanical properties of the samples. The results show that after RE-Ti compound modification, the distribution and morphology of carbide are improved, and with the Ti increase, the impact toughness significantly increases, and tensile strength has a slight increase, but hardness is almost unchanged. When Ti content is 0.6%, the impact toughness and tensile strength are 14.9 J/cm2 and 634 MPa, respectively, reaching or approaching to the mechanical properties of the forged Cr12MoV steel.


2013 ◽  
Vol 834-836 ◽  
pp. 816-819 ◽  
Author(s):  
Li Jun Tan ◽  
Jun Qiao Wang ◽  
Qing Qun Wang ◽  
Xin Long Chen ◽  
Si Zhu Zhou

The tensile and impact properties of SAE4320 and SAE8620 alloys were investigated. Various heat treatments were applied to these two alloys, including different pre-heat treatment. The results shown that after Carburizing and Quenching, both SAE4320 and SAE8620 alloys were highly sensitively to V-notches for their impact samples. In any case, SAE4320 alloy revealed higher tensile strength, better impact toughness and deformation property. Previous work shown that after Carburizing and Quenching, the impact toughness of SAE8620 alloy was too low, the products made of it was very dangerous. Based on the results, a new advanced product was made of SAE4320 alloy instead of SAE8620 alloy. And the new product exhibited good properties. The impact value of the new product far exceeded the older products.


2018 ◽  
Vol 786 ◽  
pp. 57-64 ◽  
Author(s):  
Ahmed Hamed ◽  
Mamdouh Eissa ◽  
Abdelhakim Kandil ◽  
Omnia Ali ◽  
Taha M. Mattar

This work aims at designing and developing low carbon steel alloys to meet the high tensile strength, high ductility and high impact toughness properties. The effect of solid solution mechanism, precipitation hardening, as well as grain refinement were developed with different Manganese content (0.78-2.36wt%) combined with Vanadium(0.008-0.1wt%) and Titanium (0.002-0.072wt%) microalloying additions. The controlled thermo-mechanical treatments and chemical compositions play a big role in developing the microstructure and the corresponding mechanical properties. Therefore, the studied chemical compositions were treated thermo-mechanically by two different ways of changing start and finish forging temperatures with subsequent air cooling. The first way by start forging from 1050 to 830oC and the second from 950 to730oC. The second way of forging process developed finer grain sizes and higher ultimate tensile strengths for all the studied steel alloys. In spite of finer grain sizes, the impact toughness value was lower in the second regime due to detrimental influence of precipitation strengthening in the ferrite. A combination of 544 MPa yield strength, 615 MPa ultimate tensile strength, 20% elongation and 138 Joule impact toughness has been attained.


Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 172 ◽  
Author(s):  
Fei Zhang ◽  
Yang Yang ◽  
Quan Shan ◽  
Zulai Li ◽  
Jinfeng Bi ◽  
...  

Herein, the effects of height-diameter ratios (H/D) on the microstructure evolution and mechanical properties of 0.4C-Si-Mn-Cr steel during high temperature deformation are reported. The compression experiments were performed on steel samples using Gleeble to obtain a reasonable deformation temperature, and the degree of deformation was assessed in the range of 1.5 to 2.0 H/D via forging. The forged specimens were quenched using the same heat treatment process. The hardness and impact toughness of the steel samples were tested before and after heat treatment. Grain sizes gradually increased with an increase in the compression temperature from 950 °C to 1150 °C, and the grain sizes decreased with an increase in H/D. The microstructure of the steel samples contained pearlite, bainite, martensite, and retained austenite phase. The microstructure after forging was more uniform and finer as compared to that of as-cast steel samples. The hardness and impact toughness of the steel samples were evaluated after forging; hardness first increased and then decreased with an increase in H/D, while the impact toughness continuously increased with an increase in H/D. Hence, the microstructure and properties of steel could be improved via high temperature deformation, and this was primarily related to grain refinement.


Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Yan Han ◽  
Fei Zhao ◽  
Yuan Liu ◽  
Chaowen Huang

In this paper, the relationships between the thermomechanical treatments (TMT), the microstructural evolution the mechanical properties of Ti17 alloy were investigated. The results indicate the coarsening behavior of lamellar α was sensitive to the aging temperature during the process of TMT. The thickness of lamellar α changed from 0.19 to 0.38 μm with an increase in the aging temperature. Moreover, both tensile properties and impact toughness vary with the thickness of lamellar α. The tensile strength increases with the increase of the thickness of lamellar α the plasticity and impact toughness the opposite trend. The quantitative investigations found that there is a linear relationship between the tensile properties and the thickness of lamellar α the tensile properties could be adjusted in the range of 1191~1062 MPa and 1163~1039 MPa to obtain ultimate tensile strength and yield strength as well as 11~16% elongation and 23~33% reduction of area by varying the thickness of lamellar α. Meanwhile, the impact toughness could be adjusted in the range of 46 ~53 J/cm2. The high correlation coefficients imply that the linear equation is reliable to describe the relationships between the mechanical properties and the thickness of lamellar α for Ti17 alloy.


2017 ◽  
Vol 898 ◽  
pp. 401-406
Author(s):  
Qun Gong He ◽  
Jun Liu ◽  
Lin Xu Li ◽  
Zhen Huan Gao ◽  
Xiao Yan Shi ◽  
...  

The microstructures and mechanical properties of IN738LC superalloy made by investment castings followed by Hot Isostatic Pressing (HIP) treatment have been investigated. The results revealed that after HIP treatment, the microporosities have been almost removed and the density rose by 0.21%. The eutectic size became smaller and the fraction decreased. The γ' phase was more regular and also increased in size, while a large number of secondary γ' phase appeared. With HIP treatment, the impact toughness increased from 5.0J ~ 7.0J to 8J ~ 9J and tensile strength at 200°C ~ 800°C was improved by approximately 3.2%~19.7%. In addition, the ductility and the stress rupture life have also been greatly improved as well.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5243
Author(s):  
Jia Fu ◽  
Chaoqi Xia

X6CrNiMoVNb11-2 supermartensitic stainless steel, a special type of stainless steel, is commonly used in the production of gas turbine discs in liquid rocket engines and compressor disks in aero engines. By optimizing the parameters of the heat-treatment process, its mechanical properties are specially adjusted to meet the performance requirement in that particular practical application during the advanced composite casting-rolling forming process. The relationship between the microstructure and mechanical properties after quenching from 1040 °C and tempering at 300–670 °C was studied, where the yield strength, tensile strength, elongation and impact toughness under different cooling conditions are obtained by means of mechanical property tests. A certain amount of high-density nanophase precipitation is found in the martensite phase transformation through the heat treatment involved in the quenching and tempering processes, where M23C6 carbides are dispersed in lamellar martensite, with the close-packed Ni3Mo and Ni3Nb phases of high-density co-lattice nanocrystalline precipitation created during the tempering process. The ideal process parameters are to quench at 1040 °C in an oil-cooling medium and to temper at 650 °C by air-cooling; final hardness is averaged about 313 HV, with an elongation of 17.9%, the cross-area reduction ratio is 52%, and the impact toughness is about 65 J, respectively. Moreover, the tempered hardness equation, considering various tempering temperatures, is precisely fitted. This investigation helps us to better understand the strengthening mechanism and performance controlling scheme of martensite stainless steel during the cast-rolling forming process in future applications.


Alloy Digest ◽  
1953 ◽  
Vol 2 (3) ◽  

Abstract RYCROME is a chromium-molybdenum alloy steel heat treated to definite minimum mechanical properties. The combination of high tensile strength and good ductility give this alloy good shock and impact resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on low and high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-8. Producer or source: Joseph T. Ryerson & Son Inc. (Distributor).


2011 ◽  
Vol 239-242 ◽  
pp. 408-412 ◽  
Author(s):  
Peng Wen ◽  
Qi Lin Mei ◽  
Xiao Qin Yue ◽  
Meng Xin Liu

To improve brittleness and optimize interface of glass-fiber/PVC composites, reinforcing and toughening technologies for glass-fiber/PVC composites were studied. Influences of glass-fiber and diallyl orthophthalate(DAOP) resin on their mechanical properties were observed. Diallyl orthophthalate(DAOP) resin was blended with PVC in various weight ratios by melt compounding. The compatibility between diallyl orthophthalate(DAOP) resin and PVC resin was analysed by measuring the impact toughness, tensile strength and bending strength. The results clarified that each mechanical properties improved, in addition to,SEM images show that the interface of glass-fiber/PVC composites added with DAOP was much closer , PVC resin surrounds completely the glass-fiber.


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