Carbonitriding of forging tools of steel 5KhNM in the process by heating to quenching temperature

1974 ◽  
Vol 16 (9) ◽  
pp. 802-804
Author(s):  
A. N. Tarasov
Author(s):  
June D. Kim

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.


Author(s):  
J. J. Laidler

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1136
Author(s):  
Marcel Carpio ◽  
Jessica Calvo ◽  
Omar García ◽  
Juan Pablo Pedraza ◽  
José María Cabrera

Designing a new family of advanced high-strength steels (AHSSs) to develop automotive parts that cover early industry needs is the aim of many investigations. One of the candidates in the 3rd family of AHSS are the quenching and partitioning (QP) steels. These steels display an excellent relationship between strength and formability, making them able to fulfill the requirements of safety, while reducing automobile weight to enhance the performance during service. The main attribute of QP steels is the TRIP effect that retained austenite possesses, which allows a significant energy absorption during deformation. The present study is focused on evaluating some process parameters, especially the partitioning temperature, in the microstructures and mechanical properties attained during a QP process. An experimental steel (0.2C-3.5Mn-1.5Si (wt%)) was selected and heated according to the theoretical optimum quenching temperature. For this purpose, heat treatments in a quenching dilatometry and further microstructural and mechanical characterization were carried out by SEM, XRD, EBSD, and hardness and tensile tests, respectively. The samples showed a significant increment in the retained austenite at an increasing partitioning temperature, but with strong penalization on the final ductility due to the large amount of fresh martensite obtained as well.


2010 ◽  
Vol 154-155 ◽  
pp. 417-420
Author(s):  
Di Cui ◽  
He Liang

The quenching process is a complex process, which involves quenching medium flow field, work piece temperature and stress field. In this paper, the 40Cr steel belt wheel is chosen for the sample of finite element method to simulate the quenching process. The temperature changes with time at any position in the work piece are directly reflected in the actual quenching process. The cooling curves of center and general surface are obtained after simulation. Combined with cooling curve of transformation of under cooled austenite, it is easy to predict whether the technological results meet the performance of organization, and conduct a security assessment of the work piece.


CORROSION ◽  
10.5006/3763 ◽  
2021 ◽  
Author(s):  
Danbin Jia ◽  
Liangcai Zhong ◽  
Jingkun Yu ◽  
Zhaoyang Liu ◽  
Yuting Zhou ◽  
...  

The effects of morphology of ferrite and non-metallic inclusions on corrosion resistance of as-cast 304 stainless steel (304 SS) were investigated. With the decrease in quenching temperature from 1723 K to 1648 K, the different microstructures of the as-cast 304 SS were obtained as the following series: austenitic-lathy δ ferrite, austenitic-colony δ ferrite and austenitic-blocky δ ferrite, and the average inclusion size increased. The electrochemical results show that the sample with the microstructure of austenitic- lathy δ ferrite and smaller size inclusions had a higher corrosion tendency and the lower pitting resistance. Furthermore, the effect of morphology and content of ferrite on corrosion resistance was greater than that of inclusion size under the current experimental conditions. Therefore, a promising method was developed to improve the corrosion resistance of as-cast 304 SS by changing the solidification process.


2012 ◽  
Vol 706-709 ◽  
pp. 2734-2739 ◽  
Author(s):  
Hana Jirková ◽  
Ludmila Kučerová ◽  
Bohuslav Mašek

The use of the combined influence of retained austenite and bainitic ferrite to improve strength and ductility has been known for many years from the treatment of multiphase steels. Recently, the very fine films of retained austenite along the martensitic laths have also become the centre of attention. This treatment is called the Q-P process (quenching and partitioning). In this experimental program the quenching temperature and the isothermal holding temperature for diffusion carbon distribution for three advanced high strength steels with carbon content of 0.43 % was examined. The alloying strategies have a different content of manganese and silicon, which leads to various martensite start and finish temperatures. The model treatment was carried out using a thermomechanical simulator. Tested regimes resulted in a tensile strength of over 2000MPa with a ductility of above 14 %. The increase of the partitioning temperature influenced the intensity of martensite tempering and caused the decrease of tensile strength by 400MPa down to 1600MPa and at the same time more than 10 % growth of ductility occurred, increasing it to more than 20%.


2018 ◽  
Vol 2 (2) ◽  
Author(s):  
A. Noor Setyo HD ◽  
Sri Widodo

This study aims to determine the Hardness and Toughness of cast iron after undergoing a Tempering process with independent variables heating time and dependent Hardness, microstructure and toughness Impack. Quenching was carried out at temperatures of 7750C, 8000C and 8250C in cold water media, while Tempering was carried out at temperatures of 2000C, 3000C and 4000C with a holding time of 15 minutes. Vickers Hardness test results using "Micro Hardness Tester" after Quenching have increased by an average of 95.6% at Quenching 7750C, 99.8% at Quenching 8000C and 107.1% at Quenching temperature 8250C from Hardness value of row material of 256.6 BHN or 260.8 VHN0,040. The maximum hardness value is obtained 531.4 BHN or 553.6 VHN 0,040 at Quenching temperature 8250C and the lowest Hardness of 501.8 BHN or 541,8 VHN0,040 at Quenching 7750C temperature, has Cementite phase as a matrix with little Martensite, is due to treatment The partial tempering of Martensite is replaced by the ferrite phase between Cementites. The results of the study concluded that at Tempering temperatures of 2000C, 3000C and 4000C, the toughness of FC 30 experienced an increase of 106.5%, 121.9% and 130.5% from the initial energy of 5.21 Joule / mm2, whereas violence decreased by 88, 6%, 80.8% and 40.4% of the original Hardness of 260.8 VHN 0,040


1979 ◽  
Vol 53 (1) ◽  
pp. K31-K33
Author(s):  
F. Hashimoto ◽  
Y. Kamiura ◽  
H. Takahashi

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