Mechanical Properties Of Forgings Research Articles

Условия кристаллизации слитков высокопрочных алюминиевых сплавов с повышенным содержанием циркония

The structure of model alloys of the aluminum-zirconium system and industrial 1973-type alloy with an increased content of zirconium after rapid cooling to temperatures of the liquid-solid region and isothermal holding at these temperatures has been studied. It is shown that during primary crystallization of intermetallic precipitates with low crystallization rate, it is advisable to use the model of decomposition of supersaturated solid solutions. It was determined that formation of Al3Zr particles leads to zirconium decrease in the solid solution in center and grain boundary. Under certain crystallization conditions, there is an incubation period for the zirconium intermetallic compounds precipitation. It is shown that the incubation period for aluminum with 0.25 % zirconium is more than 2 minutes, and for 0.5 % zirconium — less than 0.5 minutes. The value of the dendritic parameter of the 1973-type alloy with an increased zirconium content during two-stage crystallization corresponds to the known regularity of the change in the dendritic parameter depending on the cooling rate. Casting of alloy ingots of 1960-type alloy with 0.27 % Zr by the two-stage cooling with the use of a water-cooling tray has been tested. This made possible to produce ingots with 84 mm diameter without the formation of primary intermetallic compounds. The mechanical properties of forgings from such ingots showed an increase in ductility by 20 % while maintaining the strength characteristics.

Development of microstructure and mechanical properties of forgings in the thermomechanical treatment

Development of microstructure and mechanical properties of forgings in the thermomechanical treatment

Micro-alloyed steels for forgings: effect of nano-precipitation on mechanical properties

The aim of the present paper deals with the production of heavy steel forgings of micro-alloyed steels. Improvements of mechanical properties of forgings up to level by sheets, strips and tubes have been achieved by mean of application of micro-alloying elements and thermo-mechanical treatments. The effect of vanadium addition has been assessed by means of metallurgical modelling step followed by a laboratory demonstration phase by means of ingot manufacturing. Heat treatment has been designed aimed to achieve the desired target tensile properties. Results show that ASTM A694 F70 grade requirements can be fulfilled by 0.15% V addition and a proper heat treatment in a ferrite-pearlite microstructure, representative of a forged component.

Microstructural modeling and numerical simulation of multi-physical fields for martensitic stainless steel during hot forging process of turbine blade

The mechanical properties of forgings mainly depend on the microstructure evolution during closed-die forging process, during which the microstructure mainly undergoes dynamic recovery, dynamic recrystallization, static recovery, static recrystallization, and metadynamic recrystallization. The macroscopic factors such as deformation temperature, strain rate, and strain play a key role in the microstructure evolution when the material composition is given. This paper presents the mathematical models for the prediction of microstructure evolution for martensitic stainless steel based on the hot compression test. A coupled analysis system of flow stress field, temperature field, and microstructure evolution for hot forging was developed based on the commercial software. The forging process of martensitic stainless steel turbine blade was simulated by the developed system. The influence of initial temperature of billet and deformation velocity on the load and finial temperature of forging part was analyzed. The variation of strain, temperature, and recrystallization volume fraction and grain size has been analyzed through simulation of the forging process. Based on the simulation results, the optimum hot forging process for complex forging parts was obtained.

Elaboration of Thermomechanical Treatment Conditions of Ti-V and Ti-Nb-V Microalloyed Forging Steels

Abstract The goal of the work was to describe the forging conditions of thermomechanical treatment for Ti-V and Ti-Nb-V microalloyed steels. Conditions of hot-working allowing to obtain both the desired microstructure and mechanical properties of forgings were selected taking into consideration: precipitation analysis of MX-type (M – Nb, Ti, V; X – N, C) interstitial phases in austenite; research on the influence of the austenitizing temperature on the g-phase grain size; investigation of the continuous compression of specimens; and examination of the kinetics of recrystallization of plastically deformed austenite. The precipitation analysis of MX-type interstitial phases in austenite was conducted on the basis of a simplified thermodynamic model for equilibrium conditions as proposed by Adrian, assuming that individual MX phases are soluble in austenite. The effect of the austenitizing temperature in a range from 900 to 1200°C on the prior austenite grain size was investigated to verify the precipitation analysis of MX-type phases. The work also presents the results of the effect of Nb, Ti and V microadditions on flow stress, recrystallization kinetics and microstructure. Plastometric tests were carried out using the Gleeble 3800 thermomechanical test simulator. The studies provide the basis for a proper design of the manufacturing process for thermomechanical treatment of forged machine parts obtained from high-strength microalloyed steels.

Effect of Reduction Ratio and Heat Treatment on Mechanical Properties of Forgings from Steel 14Kh17N2

Results of experimental studies of the effect of reduction ratio and modes of heat treatment on the mechanical properties of two ingots of steel 14Kh17N2 in directions longitudinal and transverse with respect to the direction of the deformation are presented.

Mechanical Properties of Single-Melt PAM Processed Ti-6Al-4V Forgings

Ti-6Al-4V pancakes were manufactured by alpha-beta forging using single-melt (SM) plasma arc melt (PAM) billet stock at three oxygen levels, 0.16, 0.20 and 0.24 wt%, along with a standard double vacuum arc remelted (2XVAR) billet stock at 0.17 wt% oxygen for baseline comparison. Mechanical properties of forgings in the mill-, recrystallization- and beta-annealed conditions were then characterized by microstructure examination, tensile, smooth bar axial fatigue and fracture toughness testing in radial orientation. The effect of oxygen content on mechanical properties of the forgings was assessed. All SM PAM forgings exhibited slightly higher tensile and fatigue strength compared to those of 2XVAR. The fracture toughness values decreased with increasing oxygen content. Microstructures of all forgings were similar to those of conventional alpha-beta forgings. The data presented in this paper can be useful to designers in their efforts to introduce low-cost SM PAM Ti-6Al-4V (Ti-6-4) alloy forgings into various U.S. defense applications.

Forging Effect of Horizontal V - Shaped Anvil for Heavy Axial Forgings

Horizontal V – shaped anvil forging method is introduced to control fibrous tissue flow direction through changing shape of anvil, to improve the anisotropy of mechanical properties of forgings. This method can provide effectively drawing out technology for heavy axial forgings with requirements on the transverse mechanical properties. In this paper pilot production for rectangular billet by the forging method with horizontal V - shaped anvil were carried out. The results show that the forging method with horizontal V-shape anvil can improve transverse mechanical properties, realize uniform forging for heavy axial forgings, the ratio between transverse and longitudinal mechanical property is about 1.0 in the same position for heavy axial forgings, and uniformity degree of mechanical properties is better.

Influence of Fire Times on the Microstructure and Mechanical Properties of Forgings with Complex Shape

Influence of Fire Times on the Microstructure and Mechanical Properties of Forgings with Complex Shape

塑性加工 鍛造における数値シミュレーション技術の現状と動向

To reduce the development and production lead time, and to make precise parts are main targets in forging industry. With the increasing computational power and the advances in software, development in the finite element modeling of forging processes became more and more realistic. The finite element methods (FEM) are now applicable for not only 2D but also 3D problems. Material flow, forging defects, temperature rise, elastic deformation of tools as coupled problem, tool life, microstructure and mechanical properties of forgings and residual stress and distortion after heat treatment can be predicted using FEM by personal computer. Until recently, the limitation in virtual modeling was given by the capacity of the computers. Consequently users have been forced to reduce their models. But with the permanently increasing computer capacity, the main focus begins to switch back to the problems of the modeling and the determination of the parameter data.

Magnetic method for quick nondestructive evaluation of the mechanical properties of forgings

Magnetic method for quick nondestructive evaluation of the mechanical properties of forgings

An investigation of the uniformity of mechanical properties of forgings of VT9 titanium alloy after superplastic deformation and high-temperature thermomechanical processing

The results are presented of evaluation of the uniformity of mechanical properties and structure of VT9 alloy after deformation with different degrees under conditions of superplasticity and high-temperature thermomechanical working. It is shown that the strength and plastic properties of forgings of this alloy after superplastic deformation with degrees from 10 to 70% are stable and quite high. The macro- and microstructures of such forgings and uniform. High-temperature thermomechanical working with an increase in the degree of deformation leads to a reduction in plasticity an an increase in strength with a significant spread in properties apparently related to the structural nonuniformity. The results obtained make it possible to evaluate the advantages of treatment under conditions of superplasticity and in comparison with high-temperature thermomechanical working. 7 refs., 1 fig., 1 tab.

Quenching of small forgings of structural steels from the forging temperature

1. The variation of the degree of plastic deformation from 10 to 90% during forging has no significant effect on the mechanical properties of forgings of steel No. 45 quenched from the forging temperature. 2. The mechanical properties of forgings of steels No. 45 and 40Kh change little after the end of forging and quenching with additional colling from 950, 900, 850, and 800°C. 3. Quenching after the end of forging at different temperatures and different degrees of deformation makes it possible to obtain better mechanical properties as compared to those indicated by the TU specifications. 4. We have shown that it is feasible to quench small forgings of steel No. 45, 40Kh, and 0Kh18N10T from the forging temperature. 5. For 0Kh18N10T steel decrease in the forging temperature and subsequent quenching from 1000 to 800°C increases the strength.

Quenching of large forged pieces from the forging temperature

1. No cracks form in 300 mm samples of steel No. 45 quenched directly after forging and subsequently tempered regardless of the area of the original ingot from which the sample was made. No cracks are formed in 300 mm samples of 40KhN steel quenched from the forging temperature, and the steel acquired immunity to crack formation: no cracks occur after subsequent heat treatment — quenching followed by tempering at high temperatures. Samples 500 mm in diameter of 40KhN steel made from the top of the ingot may develop cracks after quenching from the forging temperature. 2. The mechanical properties of forgings 300 mm in diameter made from carbon steel No. 45 satisfy the technological requirements after quenching from the forging temperature followed by tempering at high temperatures. 3. The results of the experiments lead us to recommend quenching from the forging temperature to prevent crack formation in medium carbon steel up to 500 mm in diameter and in alloyed steels (40KhN, 40Kh, 34KhM, 50G, 60G, 40KhNM, etc.) up to 300 mm in diameter instead of the usual prolonged annealing after forging.