Square steel back corrugated, is the long waist of the I-shape and short waist corresponding Mosaic composition. Generally, there are two kinds of equilateral Angle steel and unequal Angle steel. 1. According to the national standard GB/T25276-2006 "Seamless steel pipe for mechanical equipment" technical conditions: 2. The allowable deviation of wall thickness was ±4%. 3. The allowable tolerance for outer diameter is plus or minus 5% (+6% for large size). The cold bending equipment is used to produce the square steel back, the process is simple and the cost is low. In existing high-level residential building template back stare blankly system adopt wood square is given priority to, but with the rapid development of the national housing construction, wood square resources of deforestation is finding it hard to grow is proportional to the condition of the domestic building (resources gap is more and more big, the damage to the environment is becoming more and more serious, how to meet the needs of the construction of, become a most pressing problem. Replacing wood with square steel is forced by the situation. Steel and metal materials are used to replace wood resources, new building formwork support system is used, and square steel is widely used. Through the cost analysis, not only can reduce the construction cost, improve the quality of construction engineering, but also can reduce the loss of wood resources in the construction process, replace wood with steel, save the cost, but also save a lot of forest resources. Forests are closely related to production and construction. Land and forests provide raw materials for production and construction. Forest is a biological community with woody plants as the main body. It is a total ecological system formed by the interdependence and restriction between the concentrated trees and other plants, animals, microorganisms and soil, and the mutual influence with the environment. With its rich species, complex structure and diverse functions, the forest is known as the "lungs of the earth". Productive construction can directly increase the production capacity of all sectors of the national economy, improve the technical level of fixed assets, change the industrial structure, and is also the material and technological basis for non-productive construction. In arranging capital construction investment, we should also properly handle productive construction and investment