Deformation Characteristics and Mechanism of Martensitic Stainless Steel during Thixoforming

2014 ◽  
Vol 217-218 ◽  
pp. 195-200
Author(s):  
Ren Bo Song ◽  
Ya Ping Li ◽  
Yong Jin Wang ◽  
Cui Qing Zhao
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Martensitic Stainless Steel ◽  
Testing Machine ◽  
Functionally Graded ◽  
Deformation Resistance ◽  
Liquid Region ◽  
Deformation Characteristics ◽  
Semi Solid

Semi-solid billet of 9Cr18 martensitic stainless steel with globular grains was made by a wavelike sloping plate experimental device, and hot compression tests were carried out in the semi-solid state of 9Cr18 semi-solid billet on Gleeble-1500 thermal simulation testing machine at the temperatures of 1250°C ~1300°C and the strain rates of 0.1 s-1~5.0 s-1to investigate the effects of thixoforming parameters on its deformation characteristics and mechanism. According to the true stress-strain curves obtained from the test, the influence of deformation temperature and strain rate on 9Cr18 semi-solid billet deformation resistance was investigated, and the deformation resistance model of specimen with coexistence of solid and liquid phases was established. In this paper, it was found that deformation mechanism changed because of different deformation temperature and strain rate. Dynamic recrystallization occured at 1250°C in different phases separately. So that big fine recrystallized grains were achieved at the soft primary austenite region while small recrystallized grains were achieved at the hard solidified liquid region. The melted metal would be extruded from the centre of the specimen to the free surface completely when the temperature was higher than 1275°C. And then specimen became FGM (functionally graded materials), with phases and properties graded distribution perpendicular to the stress direction. When thixoforming temperature reached 1300 °C, martensitic transformation occurred after rapid cooling. The mathematics models of the relation between stress and temperatures, fraction of solid, deformation rates and deformation degree of 9Cr18 semi-solid billet were regressed and established based on the dates attained from the compression deformation experiments. The R value was 0.991, and the RMSE value was 3.57.

Deformation Behavior of Semi-Solid ZCuSn10P1 Copper Alloy during Isothermal Compression

2016 ◽  
Vol 256 ◽  
pp. 31-38
Author(s):  
Jia Wang ◽  
Rong Feng Zhou ◽  
Han Xiao ◽  
De Hong Lu ◽  
Lu Li ◽  
...  
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Copper Alloy ◽  
Deformation Resistance ◽  
Experimental Results ◽  
Isothermal Compression ◽  
Compression Tests ◽  
Sima Process ◽  
Semi Solid

The isothermal compression tests of semi-solid ZCuSn10P1 alloy by strain induced melt activation (SIMA) process are carried out by Gleeble-1500 thermo-mechanical simulator, and the same tests are finished to samples of as-cast ZCuSn10P1 alloy. The deformation temperature respectively is 910°C, 920°C and 930°C, and the strain respectively is 0.4 and 0.6, the strain rate is 0.5s-1, 1s-1 and 10s-1. The experimental results indicate that the deformation resistance of semi-solid ZCuSn10P1 copper alloy with smaller, more uniform and rounder solid grain is about half of the as-cast ZCuSn10P1 copper alloy. The deformation resistance of ZCuSn10P1 alloy by SIMA process decreases with the deformation temperature increasing, and the deformation resistance increases with the strain rate increasing.

Semi-Solid Deformation of Al-Fe Alloy Prepared by Electromagnetic Stirring

2010 ◽  
Vol 152-153 ◽  
pp. 726-733 ◽  
Author(s):  
Bo Liu ◽  
Xiao Guang Yuan ◽  
Hong Jun Huang ◽  
Shao Hua Zhang
Keyword(s):  
Strain Rate ◽  
Solid Fraction ◽  
Deformation Temperature ◽  
Strain Softening ◽  
Testing Machine ◽  
Materials Testing ◽  
Solid Alloy ◽  
Solid Deformation ◽  
Semi Solid ◽  
Peak Value

The semi-solid compression behaviors and the microstructure of Al-Fe alloy prepared by electromagnetic stirred were investigated in the strain rate range of 5×10-3 s-1 to 5×10-1 s-1 and the temperature range of 610 to 640°C on INSTRON-5500R materials testing machine. The experimental results showed that, during the semi-solid deformation of Al-Fe alloy，the peak value of true stress decreased with elevating deformation temperature. As the deformation increased, the stress peak value of the high solid fraction alloy was tending upwards, and that of the low solid fraction was tending downwards. The peak increased with increasing the strain rate. Al-Fe alloy was sensitive to strain rate during semi-solid compression. The strain softening phenomenon would happen. The smaller strain rate, the longer softening process, the stress falling was more slowly. The strain softening was a reason that the semi-solid alloy structure was instability during deformation. The semi-solid deformational behaviors of Al-Fe alloy was bound up with deformation temperature, strain rate, and deforming extent.

scholarly journals Effects of Low-Temperature Tempering on Microstructure and Properties of the Laser-Cladded AISI 420 Martensitic Stainless Steel Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 451 ◽  
Author(s):  
Hongmei Zhu ◽  
Yongzuo Li ◽  
Baichun Li ◽  
Zhenyuan Zhang ◽  
Changjun Qiu
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Martensitic Stainless Steel ◽  
Testing Machine ◽  
Industrial Applications ◽  
Slight Reduction ◽  
Micro Hardness ◽  
Microstructure And Properties ◽  
Steel Coating ◽  
Aisi 420

Post-treatment is crucial to improve the comprehensive performance of laser-cladded martensitic stainless steel coatings. In this work, a low-temperature tempering treatment (210 °C), for the first time, was performed on the laser-cladded AISI 420 martensitic stainless steel coating. The microstructure and properties of the pre- and post-tempering specimens were carefully investigated by XRD, SEM, TEM, a micro-hardness tester, a universal material testing machine and an electrochemical workstation. The results show that the as-cladded AISI 420 stainless steel coating mainly consisted of martensite, austenite, Fe3C and M23C6 carbides. The phase constituent of the coating remained the same, however, the martensite decomposed into finer tempered martensite with the precipitation of numerous nano-sized Fe3C carbides and reverted austenite in the as-tempered specimen. Moreover, a slight reduction was found in the micro-hardness and tensile strength, while a significant increase in elongation was achieved after tempering. The fractography showed a transition from brittle fracture to ductile fracture accordingly. The as-tempered coating exhibited a striking combination of mechanical properties and corrosion resistance. This work can provide a potential strategy to enhance the overall properties of the laser-deposited Fe-based coating for industrial applications.

Influence of plastic deformation temperature on the structure and mechanical properties of low-alloy copper alloys with Co, Ni and B

2017 ◽  
Vol 84 (2) ◽  
pp. 49-57 ◽  
Author(s):  
B. Grzegorczyk ◽  
W. Ozgowicz
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Strain Rate ◽  
Minimum Temperature ◽  
Deformation Temperature ◽  
Tensile Testing ◽  
Copper Alloys ◽  
Testing Machine ◽  
Temperature Range ◽  
Ductility Minimum

Purpose: This work presents the influence of chemical composition and plastic deformation temperature of CuCoNi and CuCoNiB as well as CuCo2 and CuCo2B alloys on the structure, mechanical properties and, especially on the inter-crystalline brittleness phenomenon and ductility minimum temperature effect in tensile testing with strain rate of 1.2·10-3 s-1 in the range from 20°C to 800°C. Design/methodology/approach: The tensile test of the investigated copper alloys was realized in the temperature range of 20-800°C with a strain rate of 1.2·10-3 s–1 on the universal testing machine. Metallographic observations of the structure were carried out on a light microscope and the fractographic investigation of fracture on an electron scanning microscope. Findings: Low-alloy copper alloys such as CuCo2 and CuCo2B as well as CuCoNi and CuCoNiB show a phenomenon of minimum plasticity at tensile testing in plastic deforming temperature respectively from 500°C to 700°C for CuCo2, from 450°C to 600°C for CuCo2B and from 450°C to 600°C for CuCo2B and from 500°C to 600°C for CuCoNiB. Practical implications: In result of tensile tests of copper alloys it has been found that the ductility minimum temperature of the alloys equals to about 500°C. At the temperature of stretching of about 450°C the investigated copper alloys show maximum strength values. Originality/value: Based on the test results the temperature range for decreased plasticity of CuCoNi and CuCoNiB as well as CuCo2 and CuCo2B alloys was specified. This brittleness is a result of decreasing plasticity in a determined range of temperatures of deforming called the ductility minimum temperature.

Evaluation of Two Different Energy Inputs for Deposition of Stellite 6 by Laser Cladding on a Martensitic Stainless Steel Substrate

2015 ◽  
Vol 1119 ◽  
pp. 628-632
Author(s):  
Alain Kusmoko ◽  
Druce Dunne ◽  
Hui Jun Li
Keyword(s):  
Stainless Steel ◽  
Laser Cladding ◽  
Martensitic Stainless Steel ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Testing Machine ◽  
Wear Testing ◽  
Chemical Compositions ◽  
Stellite 6 ◽  
Energy Inputs

Stellite 6 was deposited by laser cladding on a martensitic stainless steel substrate with energy inputs of 1 kW (MSS-1) and 1.8 kW (MSS-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the MSS steel substrate with the lower heat input (MSS-1). Further, the Stellite coating for MSS-1 was significantly harder than that obtained for MSS-1.8. The wear test results indicated that the weight loss for MSS-1 was much lower than for MSS-1.8. It is concluded that the lower hardness of the coating for MSS-1.8, markedly reduced the wear resistance of the Stellite 6 coating.

Hot Tensile Deformation Behaviors of an AISI 316LN Stainless Steel

2015 ◽  
Vol 817 ◽  
pp. 367-373
Author(s):  
Xiao Ya Yang ◽  
Xi Tao Wang ◽  
Gen Qi Wang
Keyword(s):  
Experimental Data ◽  
Stainless Steel ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Tensile Deformation ◽  
Deformation Condition ◽  
Percentage Reduction ◽  
Deformation Behaviors ◽  
Hot Tensile Deformation ◽  
Reduction Of Area

The hot tensile deformation behaviors of 316LN austenitic stainless steel (ASS) were studied on a Gleeble-1500D thermal simulator under the deformation temperature of 1173-1473 K and strain rate of 0.01-1 s-1. The effects of deformation temperature and strain rate on hot deformation behaviors were analyzed. Based on experimental data, the constitutive equation was established, and the predicted peak stresses by the developed model agree well with the experimental data. Microstructure near the fracture and the percentage reduction of area were studied, and the results showed that the microstructural evolution has great influences on the percentage reduction of area. Under the deformation temperature of 1473K with the strain rate of 1s-1, the grain was the finest and most homogenous, and in this deformation condition the percentage reduction of area was the highest of 79.8%.

Study of Hot Formability of High Nitrogen Martensitic Stainless Steel

2008 ◽  
Vol 604-605 ◽  
pp. 279-284 ◽  
Author(s):  
Mohamad El Mehtedi
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Working Conditions ◽  
Processing Map ◽  
Martensitic Stainless Steel ◽  
High Nitrogen ◽  
Flow Curves ◽  
Hot Torsion ◽  
Working Response ◽  
Safe Working

Alloying high-chromium steels with Nitrogen leads to increase in strength, fatigue life and corrosion resistance, but reduce ductility and could induce cracks formation during forging. In order to address these problems, the hot working response of a high Nitrogen martensitic stainless steel (Fe-16.2%Cr-1.1%Mo-0.33%N-0.34%C) has been investigated by means of hot torsion tests up to rupture, in the temperature and strain rate ranges of 900-1200°C and 0.005-5 s-1 respectively. The peak stresses of the flow curves were related to strain rate (e&) and temperature (T) by the well known sinh equation. The ductility and the safe working conditions were presented in terms of processing map. The microstructure of the steel in the quenched state after deformation was analyzed by means of optical microscopy; the differences in term of morphology and distribution of the various constituents were discussed.

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