ABSTRACTPurpose: The purpose of this paper is to evaluate the influence of technological parameters of flattening in the ball rolling mill on spread and geometrical properties of strips made of stainless steel of 1.4310 type and to obtain mathematical models of flattening process.Design/methodology/approach: Flattening was performed in ball rolling mill in which cylindrical rollers have been replaced with balls of ~ 15mm diameter. Due to small dimensions to be measured we suggested the method of vector measurement of digital image. In order to evaluate the influence of technological parameters of flattening process, experimental planning method was used. The adoption of fractional experiment plan of 35-1 type enabled to reduce the number of experiments to 81, despite 5 variables.Findings: The results of performed tests have shown that strip spread is dependent on ball roughness, used draft, relation of wire diameter to ball diameter, back tension stress. The influence of tension stress has not been proved. 41554
Strip flatness depends on used draft. Observations have proved good quality of strip edges. No fractures have been detected, even in the case of flattening by means of big draft. Strip surface was of good quality.Research limitations/implications: Test results we have obtained indicate usefulness of research method that has been used as far as determination of influence of flattening process technological parameters on spread and strip geometrical properties are concerned. It has also been proved that it is purposeful to replace cylindrical rollers with balls in rolling mills.Practical implications: Flattening process mathematical models enable to assess rational procedure of flattening process parameters selection in a ball rolling mill, that determines obtaining of the required geometrical characteristics of strips.
The results can be used directly when manufacturing strips for springs made of stainless steel 1.4310.Originality/value: Uniform thickness throughout strip width, parallel flat surfaces, narrow dimension tolerance, good surface quality and naturally rounded side edges make it presumable that flattening method by means of ball-shaped tools is likely to become an accepted method of metal strips with required flatness manufacturing.Keywords: Plastic forming;  Ball rolling mill; Stainless steel; Experimental planning 1. Introduction The  development  of precision  industry  is  responsible for constant  increase of demand for narrow and thin steel strips with small dimension tolerance  and functional  characteristics  fit for respective usage. New solutions are being sought both in the area of equipment  for strip  production and technologies of strip production. Selection of the  best technology of narrow  and thin strip production depends among other  things on type of material the  strip  is to  be  made of,  its  final dimensions and properties, requirements concerning surface and edge quality. An efficient method of strip manufacturing is their  flattening in  ball rolling mill.  In this unique and prototypical machine
1.   I ntroduction cylindrical rollers  have been  replaced with  balls  of ~ 15mm diameter. The roller is used for flattening wires with  diameter below 0,5 mm. Proper  selection technological  parameters of wire  flattening process determines obtaining of  strips with  required functional characteristics  and geometrical properties.  The  paper presents evaluation of the  influence of technological  parameters of flattening process in the ball rolling mill on spread and flatness of rolled strips  made  of hardened stainless steel of 1.4310 type. Experimental planning method  enabled to obtain  flattening process mathematical  models  thanks  to  which  it is possible to design and control  production process in such  a way  to  obtain strips of required dimensions, with  required geometrical properties.Stainless steel of austenitic structure, selected for tests, is very plastic when in softened state, but its strength properties are  low. Their increase can be obtained  thanks  to  cold working, for example by drawing and flattening. Wire  and strips are used among other things for production of elastic and joined elements. They also serve for production of strings,  medical equipment, devices for chemical and food industries [1-7]. 细长不锈钢带的展平英文文献和中文翻译:http://www.751com.cn/fanyi/lunwen_41639.html