Cold roll forming the history of cold forming

Foreign roll-forming technology process has a history of more than 100 years, roughly divided into three stages.

The first stage (1838-1909) is the exploration and trial phase, this stage of roll-forming theory and cold-formed steel research work is slow. With the rapid development of industrial transportation, roll-forming process of cold-formed steel has been unable to meet user requirements.

The second stage (1910 a 1959) is the creation and gradual promotion of roll-forming cold-formed molding process stage.

The third stage (1960 to the present) is the rapid development of roll-forming production stage. Foreign cold-formed steel production development trends, summarized, there are several aspects:

1). Increasing production

Since the sixties of this century, foreign cold-formed steel production has increased rapidly, which is the general trend, according to the cold-formed steel statistics in various countries over the years, the production of cold-formed steel production and steel production is relatively stable in a certain ratio, generally 1.5:100 to 4:100. such as the former Soviet Union in 1975, developed in the development of the plan in 1990 cold-formed steel production in the proportion of steel production. Production in the proportion of steel production will reach 4%, with the improvement of cold-formed steel production process, product specifications and varieties continue to increase the quality of products continue to improve, the application of the expanding range of the former Soviet Union in 1979 on the original development plan to re-regulate the provisions of the 1990 will reach 5%, and a number of other countries are also planned to make the cold-formed steel production increase, and now the foreign cold-formed steel production of about 10 million tons per year, accounting for the world's total steel production, the cold-formed steel production of about 1.5:100 to 4:100. million tons per year, accounting for 3% of the world's total steel.

2). Research is in-depth

Foreign roll-type cold-formed forming theory, molding process and molding equipment research is in-depth, cold-formed steel on the practical application of the research work has also made a series of progress. For example, the former Soviet Union and the United States have used electronic computers to study the force energy parameters in cold-formed molding to explore the lowest energy-consuming deformation methods.

3). New processes continue to appear

Roll cold-formed forming process since 1910, the United States since the success of the research, after decades of improvement and refinement, the molding process is becoming more mature. With the cold-formed steel in the practical application of the technical and economic effects are increasingly recognized, cold-formed steel is widely used in all areas of the national economy. Users of cold-formed steel quality requirements are becoming increasingly stringent, requiring diversified varieties and specifications, which prompted the continuous improvement of roll-forming process to adapt to user requirements, foreign countries in the development of roll-forming process and the development of the corresponding equipment, the use of a vertical roller molding machine with insertion, molding rollers centralized adjustment of the molding unit referred to as CTA unit (Central Tool Adjustment), the straight edge of the molding unit. Straight edge molding unit.

4)The variety of products continues to increase, the product structure is constantly updated.

With the development of cold-formed steel production and the expansion of the scope of application, cold-formed steel varieties continue to increase, the product structure is constantly updated, product standards are gradually improved. With the continuous emergence of new technologies, billet materials and specifications are expanding the range of foreign production of cold-formed steel varieties of specifications have been more than 10,000, of which the cold-formed steel specifications range: billet width of 10mm a 2500mm, thickness of 0.1mm ~ 32mm. from the cold-formed steel material, before the 1970s of this century, mainly plain carbon steel, accounting for more than 90%; seventy years since! Since the seventies, through the actual application of technical and economic comparisons, to promote the use of high-strength low alloy steel, alloy steel and stainless steel, so that the proportion of plain carbon steel products declined year by year, alloy steel, high-strength low alloy steel and stainless steel products accounted for the proportion of the increase in the proportion of the year. In China, since the end of the 50s began to build cold-formed unit, has undergone a tortuous process of development, adjustment, the end of the 70s there are only 6, 80s of China's rapid development of cold-formed steel, to the 1982 output of only 16,000 tons, to 1989, more than 20 manufacturers across the country, the output has grown to more than 300,000 tons, the design capacity to reach more than 600,000 tons, of which 14 key factories in the metallurgical system. Unit 45 sets, cold-formed steel varieties and specifications are also increasing, has now reached more than 800 kinds. In the favorable form of reform and opening up, the national economic construction of steel varieties and quality put forward new requirements, the advantages of cold-formed steel gradually recognized and accepted by the people, cold-formed steel production has achieved greater development. So far there have been more than 100 sets of cold-formed unit, the annual production capacity of 1.5 million tons, **** more than 1,000 varieties of specifications.

(1) rough molding section using *** with a combination of rolls and replacement rolls, replacement of product specifications, part of the rack rolls do not have to be replaced, can save some of the rolls in reserve.

(2)Flat rolls with a combination of roll sheet, rough molding section of six racks, vertical roll group rolls tilted arrangement, small volume of rolls, than the traditional roll molding machine roll weight reduction of more than 1/3, equipment structure is more compact.

(3) Roll type curve is simple, easy to manufacture and repair, high roll reuse rate.

(4) Stable molding, the mill for thin-walled pipe and back wall pipe molding applicability, a wide range of product specifications. The first set of CR a Φ219 forming unit designed by the institute has been officially put into production in August 1992 in Tianjin Jinhai Union Steel Pipe Factory. However, whether in terms of production, quality, variety, consumption and application areas, or the level of equipment, technology level, compared with developed countries abroad, the gap is very large, with an annual output of nearly a hundred million tons of steel-producing countries, the status of the country is extremely disproportionate. Can be expected, cold-formed steel in China will have a greater development.