scholarly journals Microstructure and Mechanical Properties of 34CrMo4 Steel for Gas Cylinders Formed by Hot Drawing and Flow Forming

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1351 ◽  
Author(s):  
Yuebing Li ◽  
Wei Fang ◽  
Chuanyang Lu ◽  
Zengliang Gao ◽  
Xiakang Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Manufacturing Process ◽  
Large Diameter ◽  
Base Material ◽  
Flow Forming ◽  
Cold Flow ◽  
Microstructure And Mechanical Properties ◽  
Hot Drawing ◽  
34Crmo4 Steel ◽  
Gas Cylinders

An integral manufacturing process with hot drawing and cold flow forming was proposed for large-diameter seamless steel gas cylinders. The main purpose of this study was to find out the effects of the manufacturing process on the microstructure and mechanical properties of gas cylinders made of 34CrMo4 steel. Two preformed cylinders were produced by hot drawing. One cylinder was then further manufactured by cold flow forming. The experiments were carried out using three types of material sample, namely, base material (BM), hot drawing cylinder (HD), and cold flow-formed cylinder (CF). Tensile and impact tests were performed to examine the mechanical properties of the cylinders in longitudinal and transverse directions. Microstructure evolution was analyzed by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) to reveal the relation between the mechanical properties and the microstructure of the material. It is found that the mechanical properties of the 34CrMo4 steel gas cylinders were significantly improved after hot drawing and flow forming plus a designed heat treatment, compared with the base material. The observations of microstructure features such as grain size, subgrain boundaries, and residual strain support the increase in mechanical properties due to the proposed manufacturing process.

scholarly journals Fatigue Crack Growth Characteristics of 34CrMo4 Steel for Gas Cylinders by Cold Flow Forming after Hot Drawing

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 133
Author(s):  
Xiaojiao Xu ◽  
Chuanyang Lu ◽  
Yuebing Li ◽  
Xiakang Ma ◽  
Weiya Jin
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Stress Ratio ◽  
Base Material ◽  
Thermal Processes ◽  
Cold Flow ◽  
34Crmo4 Steel ◽  
Gas Cylinders

The fatigue crack growth (FCG) behavior of 34CrMo4 steel, a typical material for gas cylinders, has been investigated. Specimens were taken from the base material (BM) as well as the hot-drawn (HD) cylinder and cold-flow (CF) formed cylinder along the longitudinal and transverse directions. The FCG tests were conducted under different stress ratios for different materials and directions. The main purpose of this research was to explore the influences of the mechanical and thermal processes, sampling direction and stress ratio on the FCG behavior of 34CrMo4 steel. To further reveal the mechanism of crack propagation at different stages, the microstructures and fracture modes of FCG specimens were analyzed by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), respectively. The results showed that HD and CF materials exhibited better resistance to fatigue crack propagation than BM. The FCG rates of investigated materials can be accelerated by the increase in stress ratio. However, the sampling direction had little effect on the FCG rate. Finally, a driving force parameter (DFP) model was used to fit the experimental FCG data of three materials with different mechanical and thermal processes. A unified transition stage between the stable and unstable FCG stages of three materials under various experimental conditions was revealed by DFP model, playing an important role on the early warning of fatigue fracture for different types of 34CrMo4 steel.

Investigation of Microstructure and Mechanical Properties of Friction Stir Lap Jointed Ni Base Superalloy

2012 ◽  
Vol 724 ◽  
pp. 481-485
Author(s):  
Kuk Hyun Song ◽  
Kazuhiro Nakata
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Welding ◽  
Base Material ◽  
Lap Joints ◽  
Stir Zone ◽  
Inconel 600 ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

This study evaluated the microstructure and mechanical properties of friction stir welded lap joints. Inconel 600 and SS 400 as experimental materials were selected, and friction stir welding was carried out at tool rotation speed of 200 rpm and welding speed of 100 mm/min. Applying the friction stir welding was notably effective to reduce the grain size of the stir zone, as a result, the average grain size of Inconel 600 was reduced from 20 μm in the base material to 8.5 μm in the stir zone. Joint interface between Inconel 600 and SS 400 showed a sound weld without voids and cracks. Also, the hook, along the Inconel 600 alloy from SS 400, was formed at advancing side, which directly affected an increase in peel strength. In this study, we systematically discussed the evolution on microstructure and mechanical properties of friction stir lap jointed Inconel 600 and SS 400.

scholarly journals Effect of Alloying Composition on Microstructure and Mechanical Properties of Ultranarrow Gap Welded Joints of U71Mn Rail Steel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Lian Gong ◽  
Hui Liu ◽  
Cheng Lv ◽  
Lijun Zhao
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Welded Joints ◽  
Alloy Composition ◽  
Rail Steel ◽  
Base Material ◽  
Average Hardness ◽  
Microstructure And Mechanical Properties ◽  
Fine Pearlite ◽  
The Impact

A new welding method, ultranarrow gap welding with constrained arc by flux band, is proposed to compensate for the low quality of rail thermite welded joints. This article presents the results of research on the microstructure and mechanical properties of ultranarrow gap welded joints of U71Mn rail steel made using three types of alloying composition content flux bands. Results indicated that the base metal metallographic microstructure consisted mainly of pearlitic, the HAZ was mainly composed of fine pearlite, and the microstructure of the welded bead was composed of acicular ferrite, while the weld grain size decreased as the alloy composition increased. The average hardness noticeably changed in weld metal as the alloy composition increased, and when the alloy composition reached 19%, the hardness was equivalent to the base material. The average hardness value of the HAZ (35.8 HRC) was higher than that of the base metal (24.8 HRC). The tensile strength increased, and the percentage elongation after fracture decreased with increasing alloying composition from 9% to 19%. The impact absorbing energies were decreased as the alloying composition increased. Consequently, all the mechanical properties of rail ultranarrow gap welding were higher than those of the standard requirements of the rail flash welding. And the optimal alloying composition of flux band was 19%.

Effect of Process Variables on Microstructure and Mechanical Properties of Wide-Gap Brazed IN738 Superalloy

2005 ◽  
Vol 297-300 ◽  
pp. 2876-2882 ◽  
Author(s):  
Yong Hwan Kim ◽  
Il Ho Kim ◽  
C.S. Kim
Keyword(s):  
Mechanical Properties ◽  
Metal Powder ◽  
Filler Metal ◽  
Rupture Life ◽  
Base Material ◽  
Material Strength ◽  
Main Process ◽  
Process Variables ◽  
Microstructure And Mechanical Properties ◽  
Wide Gap

This study investigated the microstructure and mechanical properties of a wide-gap region brazed with various process variables. The IN738 and DF 4B alloy powders were used as additive and filler metal powder for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. The wide-gap region brazed with 60wt.% IN738 additive powder had a microstructure consisting of IN738 additive and (Cr, W)2B. The fracture strength of the wide-gap region (60 wt.% additive and 40 wt.% filler metal powder) brazed at 1230°C for 30hr was as high as 862MPa (93% of base material strength). It was observed that the brazing temperature was the main process variable affecting the mechanical properties of the wide-gap brazed region. The creep rupture life of the region brazed with 60wt.% additive and 40 wt.% was longer than that of other brazed samples. The Cracks in the wide-gap brazed region initiated at the (Cr, W)2B and propagated through them. It was found that the (Cr, W)2B and the pore in the brazed region are important microstructural factors affecting the mechanical properties of the wide-gap brazed region.

The Microstructure and Mechanical Properties of Ti-6Al-4V Alloy Bar with a Large Diameter of 450 mm

2011 ◽  
Vol 690 ◽  
pp. 473-476
Author(s):  
Wei Qi Wang ◽  
Jie Dong
Keyword(s):  
Mechanical Properties ◽  
Large Diameter ◽  
Ultrasonic Inspection ◽  
Thermomechanical Process ◽  
Aerospace Application ◽  
Class A ◽  
Uniform Microstructure ◽  
Heavy Section ◽  
Microstructure And Mechanical Properties

A special thermomechanical process has been developed in order to improve the homogeneity of the microstructure and mechanical properties of Ti-6Al-4V alloy bar with a diameter of 450 mm for aerospace application. This study has investigated microstructure and mechanical properties on the large diameter bar. It has been found that the heavy section of the bar has uniform microstructure and mechanical properties, which can meet the specifications for Ti-6Al-4V alloy bar with a diameter of 300 mm, and ultrasonic inspection can meet the specification of ASM 2631 class A.

Microstructure and Mechanical Properties a New Iron-Base Material Used for the Fabrication of Sintered Diamond Tools

2014 ◽  
Vol 1052 ◽  
pp. 520-523 ◽  
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Janusz Konstanty
Keyword(s):  
Mechanical Properties ◽  
Base Material ◽  
General Purpose ◽  
Iron Base ◽  
Bronze Powder ◽  
Microstructure And Mechanical Properties ◽  
Yield Test ◽  
Sintered Diamond ◽  
Iron Base Material ◽  
Strength And Ductility

The main objective of the present work is to characterise the microstructure and mechanical properties of a new iron-base material which has been recently gaining ground in the manufacture of diamond impregnated tools as an economical substitute for cobalt and cobalt alloys. Its density, hardness and yield test properties have been directly compared to those of hot pressed Cobalt Extra Fine (CoEF) powder. It has been shown that the raw iron-663 bronze powder mix can be consolidated to a virtually pore-free condition by hot pressing at 880°C. Although the as-consolidated material is inferior to cobalt, it displays a favourable combination of hardness, yield strength and ductility, and seems to have a great potential for moderate and general purpose applications.

Microstructure and Mechanical Properties of Cu-Cr-Zr Alloy by Friction Stir Welding

2012 ◽  
Vol 602-604 ◽  
pp. 608-611
Author(s):  
Di Qiu He ◽  
Rui Lin Lai ◽  
Shao Hua Xu ◽  
Kun Yu Yang ◽  
Shao Yong Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Rotation Speed ◽  
Base Material ◽  
Traverse Speed ◽  
Nugget Zone ◽  
Alloy Plate ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Zr Alloy

In this study, Cu-Cr-Zr alloy joints are successfully fabricated by friction stir welding (FSW). Defect-free weld are produced on 12mm thick Cu-Cr-Zr alloy plate useing a non-consumable tool with a specially designed and shoulder with a constant rotation speed and a fixed traverse speed. The effect of friction stir welding (FSW) on the microstructure and mechanical properties of Cu-Cr-Zr alloy joints are investigated in details: The joints showed the presence of various zones such as nugget zone (NZ) and thermo-mechanically affected zone (TMAZ) and base metal (BM), the microhardness and the tensile strength of welded joints are lower than that of the base material.

Sign in / Sign up

Export Citation Format

Share Document