Page 1 of 13

European Journal of Applied Sciences – Vol. 11, No. 6

Publication Date: December 25, 2023

DOI:10.14738/aivp.116.15795

Yang, C.-C., Nguyen, H. Q., & Wang, K.-H. (2023). The Forming Analysis of SCM440 Alloy Steel Hexagon Head Flange Bolts.

European Journal of Applied Sciences, Vol - 11(6). 01-13.

Services for Science and Education – United Kingdom

The Forming Analysis of SCM440 Alloy Steel Hexagon Head Flange

Bolts

Chih-Cheng Yang

Department of Mechanical and Automation Engineering, Kao

Yuan University, Taiwan

Hong Quy Nguyen

Graduate School of Metal Technology Industry, Kao Yuan

University, Taiwan

Kuo-Hsiang Wang

Graduate School of Mechatronic Science and Technology, Kao

Yuan University, Taiwan

ABSTRACT

In this study, a multi-stage cold forming process for the manufacture of hexagon

head flange bolts is studied numerically with SCM440 alloy steel. The cold forming

process through five stages includes forward extrusion, two upsetting operations,

hexagonal trimming and circular trimming. The numerical study of cold forming is

conducted using the code of DEFORM-3D. The formability of the workpiece is

studied, such as the effect on forming force responses, maximum forming forces,

effective stress and strain distributions and metal flow pattern. In the five-stage

forming process, in the two upsetting and one hexagonal trimming forming stages,

the effective stresses in the head of the workpiece are significantly high, and the

effective strains are also significantly high due to large deformation. The flow line

distributions are also very complex in which the flow lines in the trimming region

of the upset head are severely bent, highly compacted, and eventually fractured

due to excessive trimming. For the maximum axial forming force, the fourth stage,

which the head of the workpiece is heavily trimmed into a thick hexagonal shape,

is 1,360.4kN which is the largest among the five stages due to the large amount of

trimming. However, for the forming energy, the second stage, which the workpiece

is upset into a conical shape, is 9,841.0J which is the largest among the five stages

due to longer acted axial forming stroke. The total maximum axial forming forces

from the first to the last stages are 3,608.8kN and the total forming energies are

about 26.16kJ.

Keywords: cold forming, hexagon head flange bolt, formability, forming force.

INTRODUCTION

In the field of modern industry, bolts play an important role as an indispensable connecting

component in the manufacturing and maintenance of mechanical equipment. The SCM 440

alloy steel hexagon head flange bolts are high-strength bolts widely used in critical

applications. The cold forming process involves mechanical issues and is affected by material

Page 2 of 13

Services for Science and Education – United Kingdom 2

European Journal of Applied Sciences (EJAS) Vol. 11, Issue 6, December-2023

properties. Cold forming is performed at room temperature and is commonly used in many

industries, especially in the manufacture of fasteners and specialty parts.

In the cold forming process, punches and dies are subjected to high stresses. Predicting

forming forces and stresses is important for design of punch and die and the selection of

forming machine. Many cold forming applications use numerical simulation to predict and

analyze forming designs. Altan and Knoerr [1] applied the 2D finite element method to

investigate suck-in type extrusion defects, bevel gear forging, stress analysis of forging tools

and multi-stage cold forging designs. Lee et al. [2] designed a process sequence for multi-stage

cold forging with the rigid-plastic finite element method to form a constant-velocity joint

housing with shaft. They investigated velocity distributions, effective strain distributions, and

forging loads, which are useful information in process design. Joun et al. [3] proposed a

numerical simulation technique for the forging process with a spring-attached die. A penalty

rigid-viscoplastic finite element method was applied together with an iterative force- balancing method. They investigated significance of metal flow lines for quality control and

the effects of spring-attached dies on the metal flow lines and the decrease in forming load.

Roque and Button [4] applied the application of a commercial general finite element software

of ANSYS to model a forming operation. They developed models to simulate the ring

compression test and to simulate an upsetting operation which was one stage of the

automotive starter parts manufacturing process. McCormack and Monaghan [5] numerically

analyzed the cold-forging process of a hexagonal head bolt using the finite-element analysis

(FEA) code of DEFORM. The FEA analysis indicated that the highest stress concentration

occurred within the body of the tool and not along the contact surfaces.

A three-stage cold forging process to form the spline shape in the head of an aerospace

fastener was proposed by MacCormack and Monaghan [6]. They gained insight into the

operation by numerically analyzing the strain, damage, and flow patterns for all three stages.

In order to analyze the formability of the multi-stage forging process, Park et al. [7] applied

the finite element method to establish a systematic process analysis method for the multi- stage forming of a constant velocity joint outer race. Farhoumand and Ebrahimi [8] applied

the FE code ABAQUS to the analysis of the forward-backward-radial extrusion process to

investigate the influence of geometric parameters such as die corner radius and gap height

and process conditions such as friction on the process. The numerical results are compared

with experimental data in terms of forming loads and material flow in different regions. The

hardness distribution of the longitudinal section of the product was used to verify the strain

distribution obtained from the numerical analysis. Paćko et al. [9] presented an application of

the finite element analysis for prediction and optimization of a bolt forming process. The

investigated bolt forming process consisted of six stages including cutting, three upsetting

stages, backward extrusion, and trimming. Several tool modifications were proposed and

analyzed employing numerical simulation. Jafarzadeh et al. [10] applied the FE code of

DEFORM-3D to study the transverse extrusion process to analyze the effects of some

important geometric parameters such as initial billet dimensions, gap height and friction

conditions on the required forging load, material flow pattern and effective plastic strain

distribution. They showed that the gap height had the greatest influence on the forming load

and material flow. This study analyzed and compared 4 and 5 stages of fasteners. They used

the FE code of DEFORM-3D to inspect the effective stresses, strains and velocities of objects

Page 3 of 13

3

Yang, C.-C., Nguyen, H. Q., & Wang, K.-H. (2023). The Forming Analysis of SCM440 Alloy Steel Hexagon Head Flange Bolts. European Journal of

Applied Sciences, Vol - 11(6). 01-13.

URL: http://dx.doi.org/10.14738/aivp.116.15795

from billet material to finished material. Yang and Lin [11] performed numerical and

experimental studies on two forming modes for two-step extrusion forming of AISI 1010

carbon steel. The numerical results for the effective strain distributions are consistent with

the hardness distribution measured in the experiment. Al-Shammari et al. [12] designed a six- stage cold forming process using a 3D geometric model to manufacture AISI 1010 steel shells

of spark plug. They applied numerical analysis to explore product part dimensions, forging

loads, effective stresses, contact pressures, and velocity fields. The actual product part

dimensions and forging loads of the six stages were compared with the FE simulation results

to verify that the analysis results were acceptable.

A two-stage cold forging process was proposed by Ku [13] to manufacture AISI 1035 steel

drive shafts with internal spline and spur gear geometry. Obiko et al. [14] employed a three- dimensional finite element analysis using DEFORM 3D to investigate the plastic deformation

behavior during forging of X20CrMoV121 steel. They investigate the influence of forging

temperature on the strain, stress and particle flow velocity distribution during the forging

process. Francy et al. [15] dealt with input process parameter optimization in an extrusion

process using DEFORM-3D software and Taguchi approach. The simulations were conducted

by DFORM-3D software used for expecting minimum force attained in cold forward extrusion

process. Winiarski et al. [16] performed a numerical study on a six-stage cold forging process

of 42CrMo4 steel hollow flanged parts using DEFORM 2D/3D to determine whether the

proposed forging technique could be used to produce flanged hollow parts. Petkar et al. [17]

presented the use of a multi-layered feed forward artificial neural network (ANN) model to

determine the effects of process parameters such as billet size, reduction ratio, punch angle,

and land height on forming behavior, namely, effective stress, strain, strain rate, and punch

force in a cold forging backward extrusion process for AISI 1010 steel. FE simulation along

with the developed artificial neural network model scheme could benefit the cold forging

industry in minimizing the process development effort in terms of cost and time. Lee et al. [18]

proposed to use the multi-stage cold forging process to reduce the solenoid valve

manufacturing cost while satisfying dimensional accuracy and performance. The forming

process was divided into six stages to improve the dimensional accuracy of the outer diameter,

full length and slot part of the armature. Through the proposed process design for the multi- stage cold forging process, the dimensional accuracy of the test product was improved. Yang

and Liu [19] performed a numerical and experimental study on a five-stage cold forming

process for manufacturing relief valve regulating nuts with low carbon steel AISI 1010. The

numerical simulation and experimental results were in good agreement for the forming force

growth tendency. The effective strain distributions were consistent with the measured

hardness distributions. Highly compacted grain flow lines also led to higher hardness. Yang et

al. [20] numerically studied a multi-stage cold forming process for the manufacture of

eccentric parts with low carbon steel AISI 1022. The forming processes through five stages

and four stages include two-step forward extrusion, eccentric upsetting, and backward

extrusion over a moving punch. The formability of the workpiece is studied numerically, such

as the effect on forging load responses, maximum forging loads, effective stress and strain

distributions and metal flow pattern. Although the total maximum axial forging loads of the

four-stage forming are smaller than those of the five-stage forming, the maximum lateral

forging force in the last stage of the four-stage forming is almost five times that of the last

stage of the five-stage forming. Increasing lateral forging force may lead to wear and damage