Hot Deformation Behavior of Bearing Steels

2007 ◽  
Vol 129 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Ho Keun Moon ◽  
Jae Seong Lee ◽  
Sun Joon Yoo ◽  
Man Soo Joun ◽  
June Key Lee
Keyword(s):  
Testing Machine ◽  
Metal Flow ◽  
Hot Forging ◽  
Tensile Tests ◽  
Internal Crack ◽  
Compression Tests ◽  
Bearing Steels ◽  
Material Behaviors ◽  
Bearing Race ◽  
Hot Forging Process

The material behaviors of two types of bearing steels at hot working conditions are investigated. Stress-strain curves at various temperatures (900–1300°C) and strain rates (1–50/s) are obtained by compression tests with a computer controlled servo-hydraulic Gleeble 3800 testing machine. Elongation and reduction of the area are also obtained by tensile tests with the Gleeble 1500 testing machine. Flow stresses are calculated from the experiments and are used to predict the temperature distribution and the metal flow of a workpiece during a multistage hot forging process of a bearing race. A rigid-thermoviscoplastic finite element method is applied. The experimental and numerical results are summarized to reveal the reasons for internal crack formation.

Study on Cylindrical Heatsink Forging Process Considering Friction Condition

2019 ◽  
Vol 823 ◽  
pp. 141-144
Author(s):  
Tung Sheng Yang ◽  
Yong Nan Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Factor ◽  
Testing Machine ◽  
Metal Flow ◽  
Compression Tests ◽  
Stress Strain ◽  
Element Analysis ◽  
Forging Process ◽  
Different Temperatures

The feasibility of forging of AL-1050 alloy of cylindrical heatsink under warm conditions is demonstrated in the present work. The stress-strain curves and friction factor play an important role in the cylindrical heatsink forging. The purpose of forging lubrication is to reduce friction between blank and die, and to decrease resistance of metal flow to die. The stress-strain curves at different temperatures are obtained by compressing tests. The friction factor between 1050 aluminum alloy and die material are determined at different temperatures by ring compression tests with graphite lubricants. The compressing and ring compressing tests are carried out by using the computerized screw universal testing machine. The finite element method is used to investigate the forming characters of the forging process. To verify the prediction of FEM simulation in the cylindrical heatsink forging process, the experimental parameters such as stress-strain curves and fiction factor, are as the input data during analysis. Maximum forging load and effective stress distribution are determined of the heatsink forging, using the finite element analysis. Finally, the cylindrical heatsink parts are formed by the forging machine under the conditions using finite element analysis.

Testing of Materials at Medium rates of Strain

1967 ◽  
Vol 9 (4) ◽  
pp. 278-284 ◽  
Author(s):  
R. H. Cooper ◽  
J. D. Campbell
Keyword(s):  
Testing Machine ◽  
High Strength ◽  
Tensile Tests ◽  
Elastic Stiffness ◽  
Hydraulic Pressure ◽  
Compression Tests ◽  
Silicon Iron ◽  
Rate Dependent ◽  
Accuracy Of Measurement ◽  
Annealed Copper

The problems involved in the measurement of the mechanical properties of rate-dependent materials are discussed, with special reference to the role of the elastic stiffness of the testing machine and specimen. A description is given of a newly developed universal testing machine, operated by hydraulic pressure and capable of testing at crosshead velocities up to about 40 in/s. The machine has been used in two ways: for tensile tests at approximately constant strain rates in the range 10-1 to 10-2 s-1; and for compression tests in which a load is applied in a few milliseconds and maintained at a nearly constant value while the specimen is plastically deformed. The machine is instrumented so that the applied load and cross-head velocity are recorded throughout the test. The testing technique and the accuracy of measurement are discussed with reference to experimental results obtained in tests on annealed copper, mild steel, silicon-iron, and a high-strength aluminium alloy.

Material Modeling and Springback Analysis Considering Tension/Compression Asymmetry of Flow Stresses

2014 ◽  
Vol 611-612 ◽  
pp. 33-40 ◽  
Author(s):  
Nobuyasu Noma ◽  
Toshihiko Kuwabara
Keyword(s):  
Dual Phase Steel ◽  
Testing Machine ◽  
Material Model ◽  
Tensile Tests ◽  
Yield Function ◽  
Test Material ◽  
Finite Element Analyses ◽  
Compression Tests ◽  
Springback Prediction ◽  
Tension Compression Asymmetry

In-plane tension/compression tests of a dual phase steel sheet with a tensile strength of 780 MPa were carried out using in-plane stress reversal testing machine. Remarkable tension/ compression asymmetry of flow stress (TCA) has been observed. Moreover, biaxial tensile tests using cruciform specimens were performed to measure contours of plastic work. The test material exhibited differential work hardening (DWH). In order to reproduce the TCA, an asymmetric quadratic yield function proposed by Verma et al. (2011) was used. The parameters of the yield function were changed as a function of reference plastic strain to reproduce the DWH. Furthermore, to assess the springback prediction accuracy of the developed model, a 3-point bending experiment and finite element analyses (FEA) were performed. It is concluded that the use of the material model that is capable of reproducing DWH and TCA is a must for a highly accurate FEA of springback.

Flash Design for Automatic Transfer System of Bearing Hub in Hot Forging Process

2006 ◽  
Vol 116-117 ◽  
pp. 120-123
Author(s):  
Sang Kon Lee ◽  
Hyun Sang Byun ◽  
Byung Min Kim ◽  
Dae Cheol Ko ◽  
C.G. Kang
Keyword(s):  
Numerical Analysis ◽  
Metal Flow ◽  
Hot Forging ◽  
Experimental Results ◽  
Transfer System ◽  
Forging Process ◽  
Hot Forging Die ◽  
Forging Die ◽  
Hot Forging Process ◽  
Forging Load

The aim of this study is to design flash geometry of bearing hub to apply the automatic transfer system in hot forging process. The flash geometry is very important in hot forging process because the flash geometry effects on the metal flow, material losses, forging load, die pressure and so on. In this study, the problem of designing the flash geometry is studied with flash thickness and width considering the maximum die pressure to apply an automatic transfer system in hot forging process for bearing hub. The numerical analysis was conducted by means of the commercial S/W DEFORM. On the basis of numerical analysis the flash geometry of hot forging die was redesigned, and experiment was conducted. From the experimental results, it was possible to produce bearing hub with an automatic transfer system without any deterioration of die lifetime.

scholarly journals Automotive CVT sheave development using complex forging processes

2018 ◽  
Vol 7 (3.3) ◽  
pp. 329
Author(s):  
Wen Kun Peng ◽  
Sung Young Park
Keyword(s):  
Metal Flow ◽  
Hot Forging ◽  
Tensile Tests ◽  
Machining Process ◽  
Product Development Process ◽  
Cold Forging ◽  
Forging Process ◽  
Flow Test ◽  
Core Part ◽  
Material Cutting

Background/Objectives: In this study, we developed a complex forging process to produce a sheave, which is a core part of CVT for automobiles, fabricated prototypes. The existing processes such as hot forging and the MCT machining process have disadvantages including excessive amounts of material cutting, number of processes, and processing time.Methods/Statistical analysis: To overcome these shortcomings, in this study, a shape was created using hot forging and the shape was molded into a precision part using cold forging. A complex forging process was developed that enabled maximization of the metallographic density and reduction of material cutting quantity by applying a minimal number of processes. By conducting heat compression and tensile tests of the samples, we identified the physical properties of the material and used the commercial software Deform-3D to conduct a forging analysis.Findings: Based on the analysis results, we designed a combined process of hot forging and cold forging and fabricated a mold and pilot products. The fabricated pilot products were evaluated using a metal flow test, an internal defect test, a surface roughness test, etc. According to the evaluation results, no significant defect was observed, and we therefore believe it is adequate for mass production.Improvements/Applications: The complex forging method can reduce the use of material by approximately 15% compared with the hot forging and the MCT machining process. Through this study, we established a product development process using a high-precision complex forging technology.  

Investigation on metal flow and forming load of bi-metal gear hot forging process

2016 ◽  
Vol 88 (9-12) ◽  
pp. 2835-2847 ◽  
Author(s):  
Pengfei Wu ◽  
Baoyu Wang ◽  
J. Lin ◽  
Bin Zuo ◽  
Zhi Li ◽  
...  
Keyword(s):  
Metal Flow ◽  
Hot Forging ◽  
Forging Process ◽  
Forming Load ◽  
Hot Forging Process

scholarly journals The Performance of CR180IF and DP600 Laser Welded Steel Sheets under Different Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1553
Author(s):  
Mária Mihaliková ◽  
Kristína Zgodavová ◽  
Peter Bober ◽  
Anna Špegárová
Keyword(s):  
Sheet Steel ◽  
Testing Machine ◽  
Dynamic Test ◽  
Tensile Tests ◽  
Joint Surface ◽  
Strain Rates ◽  
Interstitial Free ◽  
Welded Steel ◽  
Steel Sheets ◽  
Static Tensile

The presented research background is a car body manufacturer’s request to test the car body’s components welded from dissimilar steel sheets. In view of the vehicle crew’s protection, it is necessary to study the static and dynamic behavior of welded steels. Therefore, the influence of laser welding on the mechanical and dynamical properties, microstructure, microhardness, and welded joint surface roughness of interstitial free CR180IF and dual-phase DP600 steels were investigated. Static tensile tests were carried out by using testing machine Zwick 1387, and dynamic test used rotary hammer machine RSO. Sheet steel was tested at different strain rates ranging from 10−3 to 103 s−1. The laser welds’ microstructure and microhardness were evaluated in the base metal, heat-affected zone, and fusion zone. The comprehensive analysis also included chemical analysis, fracture surface analysis, and roughness measurement. The research results showed that the strain rate had an influence on the mechanical properties of base materials and welded joints. The dynamic loading increases the yield stress more than the ultimate tensile strength for the monitored steels, while the most significant increase was recorded for the welded material.

scholarly journals Formation conditions and mechanical properties of aggregates produced in tephra–water–snow flows

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Hirofumi Niiya ◽  
Kenichi Oda ◽  
Daisuke Tsuji ◽  
Hiroaki Katsuragi
Keyword(s):  
Mechanical Properties ◽  
Mixing Time ◽  
Testing Machine ◽  
Small Scale ◽  
Scaling Analysis ◽  
Compression Tests ◽  
Ice Slurry ◽  
Experimental Conditions ◽  
Formation Conditions ◽  
Snow And Ice

Abstract The formation of aggregates consisting of snow, water, and tephra has been reported in small-scale experiments on three-phase flows containing tephra, water, and snow, representing lahars triggered by snowmelt. Such aggregates reduce the mobility of mud flow. However, the formation mechanism of such aggregates under various conditions has not been investigated. To elucidate the formation conditions and mechanical properties of the aggregates, we performed mixing experiments with materials on a rotating table and compression tests on the resulting aggregates with a universal testing machine in a low-temperature room at $$0\,^{\circ }\text {C}$$ 0 ∘ C . From experiments with varying component ratios of the mixture and tephra diameter, the following results were obtained: (i) the aggregate grew rapidly and reached maturity after a mixing time of 5 min; (ii) the mass of aggregates increased with snow concentration, exhibiting an approximately linear relationship; (iii) single aggregates with large mass formed at lower and higher tephra concentrations, whereas multiple aggregates with smaller mass were observed at intermediate concentrations; (iv) the shape of the aggregate satisfied the similarity law for an ellipsoid; (v) the compressive mechanical behavior could be modeled by an empirical nonlinear model. The obtained mechanical properties of the aggregates were independent of the experimental conditions; (vi) scaling analysis based on the Reynolds number and the strength of the aggregates showed that the aggregates cannot form in ice-slurry lahars. Our findings suggest that low-speed lahars containing snow and ice are likely to generate aggregates, but snow and ice in the ice-slurry lahars are dispersed without such aggregates.

Study of the applicability of 22MnB5 sheet metal as protective masks to improve tool life in hot forging process

2020 ◽  
Vol 107 (1-2) ◽  
pp. 39-47
Author(s):  
Luana De Lucca de Costa ◽  
Alberto Moreira Guerreiro Brito ◽  
André Rosiak ◽  
Lirio Schaeffer
Keyword(s):  
Sheet Metal ◽  
Tool Life ◽  
Hot Forging ◽  
Forging Process ◽  
Hot Forging Process
Sign in / Sign up

Export Citation Format

Share Document