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M

arch

2009

www.read-tpt.com

108

New solutions for simulation of

hot and cold tube rolling processes

Mr A Vydrin, OJSC RosNITI, Russia

Introduction

The issues of plasticity in metal working simulation have long

attracted the attention of researchers. Simulations are divided into

physical and mathematical, with computer simulation considered

a modern form of the latter. The theoretical foundations for

mathematical simulation of rolling processes were laid in the second

half of the 20th century. This was the period when the majority of

calculation formulas were obtained based on the fundamental laws

of physics, but with a number of assumptions and simplifications to

ensure analytical solutions.

The end of the 20th and the beginning of the 21st century saw

the development of computer technology and the new methods of

numerical mathematics. Universal application software packages

were developed, including Deform, Ansys, Copra, Forge3, and Marc,

that allow numerical simulations of stress-strain and temperature

conditions of metal during its plastic working phase.

However, many researchers agree that the application history of

this software used by technologists and laboratory staff shows its

ineffectiveness in plant conditions. The reason behind it is laborious

preparation of source data and long a time (up to one day or longer),

required for the computing of one option, which effectively turns it

into a research project.

On the other hand, the use of analytical relations for technological

calculations does not always produce sufficiently reliable results

that will not require further technological development in plant

conditions. The two main reasons for this are as follows:

• A wide range of steel grades and sizes leads to the excessive

laboriousness of technological parameter calculations for each

combination of grade, type and size

• In a comprehensive approach, the task is usually described by

a set of nonlinear algebraic equations that are difficult to solve

without using numerical method and computers.

Nowadays in the area of plastic metal working simulation, particularly

in tube and pipe manufacturing, there are a limited amount of

software tools for implementing modern calculating methods that

base on analytical relations of plastic metal working processes.

Currently, OJSC RosNITI is developing a comprehensive approach

to the issues of simulation that will encompass virtually all research

trends and types of simulation.

The use of turnkey application program

packages

The solution of production problems (eg those connected with metal

forming), requires dealing with a hypotheses of the physical nature,

which in most cases involves correctness that can only be proved

with the help of computer simulation. The software system Deform-

3D is used for this purpose in cooperation with the Department of

Plastic Metal Working of Yuzhno-Uralsky State University.

Defining the strained condition of the plate edge when forming

helical-seam pipes is one of the tasks that can be solved with

the assistance of software. The simulation results have proved

the existing hypothesis on the origins of ‘bamboo’ flaw (figure 1)

observed in the formed pipe weld seam area.

Practice has shown that the application CosmosWorks, part of the

SolidWorks system, is an effective tool for simulation of structural

components of the equipment working in the elastic stress zone.

The use of this application is advisable for the performance analysis

of complex configuration non-standard equipment when the existing

analytical methods cannot be used without serious simplifications

and assumptions. This software was also used to analyse strength

Figure 1

:

Stress condition pattern in cylinder shaping

Figure 2

:

Stress condition

pattern of the

tube reducing

mill of a new

design