Regularities of Thermal Diffusion Saturation with Nitrogen Combined with Standard Heat Treatment of VT22 Titanium Alloy

2017 ◽  
Vol 52 (6) ◽  
pp. 841-847 ◽  
Author(s):  
I. M. Pohrelyuk ◽  
V. M. Fedirko ◽  
S. M. Lavrys’ ◽  
T. M. Kravchyshyn
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Thermal Diffusion ◽  
Diffusion Saturation ◽  
Standard Heat Treatment ◽  
Vt22 Titanium Alloy ◽  
Standard Heat

scholarly journals Microarc surface alloying of tool steels

2018 ◽  
Vol 226 ◽  
pp. 03007 ◽  
Author(s):  
Makar S. Stepanov ◽  
Yuri M. Dombrovskii ◽  
Levon V. Davidyan
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Layer Thickness ◽  
Composite Structure ◽  
Diffusion Saturation ◽  
Standard Heat Treatment ◽  
Surface Alloying ◽  
Tool Steels ◽  
Diffusion Layer Thickness ◽  
Standard Heat

A new method of accelerating of steel diffusion saturation during thermo-chemical treatment – microarc surface alloying is proposed. The steel product is placed in a metal container filled with coal powder, and heated by passing an electric current. Powder having microarcs, which are concentrated around the surface of the product with the formation of zones of local gas discharge. This significantly speeds up the diffusion saturation. After carburizing of steel 20Cr13 is formed a diffusion layer thickness of 13-15 μm microhardness of 10.5 to 12.5 HPa, located below the eutectoid area a thickness of 300 μm and a hardness of 6.5 GPA. After boriding of steel Cr12V1 after standard heat treatment, the surface layer with a thickness of 170-180 μm consists of a base with microhardness of 9.3-9.6 GPA with inclusions of microhardness of 14.5-15.0 GPA. After boriding of steel 5CrNiMo formed a layer thickness of 250-260 μm with a composite structure consisting of sections of the eutectoid structure of microhardness of 7.0-8.0 GPA, surrounded by boride eutectic microhardness 12.0-12.5 GPA. The composite structure provides the combination of very hard boride eutectic and eutectoid plastic mixture. After boriding of steel W6Mo5Co5 after standard heat treatment, the surface layer thickness of 230-240 μm consists of a base of microhardness 11,0-11,2 GPA with inclusions of microhardness 13,5-14,5 GPA. Given the high intensity of diffusion saturation, microarc surface alloying is recommended for surface hardening of tool steels.

Fine structure of steel 5Kh3V3MFS after LTMT and standard heat treatment

1979 ◽  
Vol 21 (4) ◽  
pp. 273-277
Author(s):  
E. S. Sevast'yanov ◽  
A. I. Strikelev ◽  
I. V. Rakhov
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
Standard Heat Treatment ◽  
Standard Heat

Microstructure Evolution and Stress Rupture Properties of DD6 Single Crystal Superalloy after Overheating

2017 ◽  
Vol 898 ◽  
pp. 517-522 ◽  
Author(s):  
Shi Zhong Liu ◽  
Zhen Xue Shi ◽  
M. Han ◽  
Jia Rong Li
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Rupture Life ◽  
Stress Rupture ◽  
Standard Heat Treatment ◽  
Stress Rupture Life ◽  
Matrix Channel ◽  
Standard Heat ◽  
Stress Rupture Properties ◽  
Rupture Properties

The second generation single crystal superalloy DD6 after standard heat treatment was respectively overheated at 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1320°C for 1h and air cooled. The effect of overheating on the microstructure and stress rupture properties at 980°C/250MPa of the alloy was investigated. The results showed that the size of γ′ phase was slightly increased overheating at 1100°C, 1150°C and 1200°C. The size of γ′ phase had a big increase and its size distribution was very uneven after overheating at 1250°C. The small part of γ′ phase has serrated γ′/γ phase surface as a result of un-completely solution and the irregular small γ′ phase was in the majority when overheated at 1300°C. While all the irregular small γ′ phase precipitated again after completely solution when overheated at 1320°C. There was no fine second γ′ phase in the γ matrix channel of the alloy after standard heat treatment and overheating at 1320°C. But the fine second γ′ phase precipitated in the γ matrix channel after overheating at every temperature of 1100 °C~1300°C. No obvious change of the stress rupture life was found after overheating at 1100°C, 1150°C, 1200°C and 1250°C. The stress rupture life considerably reduced after overheating at 1300°C, whereas slightly reduced after overheating at 1320°C. The appearance of the raft had almost no change after overheating at 1100°C. With increasing of overheating temperature from 1100°C to 1250°C, the length of raft became shorter and the width thickening. The γ phase formed the wavy raft after overheating at 1300°C and 1320°C and the thickness of latter was larger than that of the former. Finally, the relationship between the microstructural evolution and stress rupture properties of the alloy after overheating was discussed.

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