| 摘要 |
PURPOSE:To prevent the deterioration of the lubricity of a treated steel material during severe cold working, by carrying out treatment with a lubricant after treatment with a phosphating soln. having a specified compsn. contg. polyaminocarboxylic acid and having an increased ratio of Ca to Zn. CONSTITUTION:When a steel material is cold worked, it is previously treated with a phosphating soln. and then treated with a lubricant. The phosphating soln. contains 0.5-3.5% Ca ions, 0.3-2.5% Zn ions, 0.5-5.0% phosphoric acid ions, 0.5-8.0% nitric acid ions, 0.0005-0.05% nitrous acid ions and 0.01-0.4% polyaminocarboxylic acid ions. In the soln., the weight ratio of Ca ions to Zn ions is regulated to 0.7-4.0. The soln. may further contain 0.01-0.4% in total of one or more among Ni, Cu and Co as required. |
