A Composite Phosphate Film Solution Formula Suitable for Hot Stamping of Ultra-High Strength Steel Sheets

Abstract

The invention relates to the field of a phosphate solution formulation. The solution is especially suitable for the phosphating process before hot stamping of an ultra-high-strength steel blank, and the surface treatment of the ultra-high-strength steel blank needs to be carried out by a composite phosphate solution. , to obtain a layer of high-temperature-resistant composite lithium iron phosphate-calcium sulfate film to improve the life of the mold. Given the chemical composition ratio according to the invention, configure a composite lithium ferrous phosphate-calcium sulfate surface treatment solution suitable for hot stamping of ultra-high-strength steel sheets: first pass iron oxide Fe2O3, lithium hydroxide LiOH H2O, hydroxide Lithium LiOH H2O, ammonium dihydrogen phosphate (NH4) 2HPO4, carbon source C to synthesize lithium iron phosphate, followed by calcium sulfate CaSO4 ultrafine powder, lithium iron phosphate ultrafine powder LiFePO4, phosphoric acid H3PO4, and distilled water H2O, according to its The mass ratio is: (40‑60): (10‑30): (5‑10): (808‑912). Put the ultra-high-strength steel blank to be treated into the phosphating solution at 55°-60°C, and the blank can obtain a dark gray phosphating film. Finally, the blank is heated to remove hydrogen to reduce the harm of hydrogen embrittlement. The saponification process is carried out to further enhance the lubrication between the hot stamping sheet and the mold.

Description

technical field [0001] The invention relates to the field of a phosphate solution formulation. The solution is especially suitable for the phosphating process of an ultra-high-strength steel blank before hot stamping. It is necessary to carry out surface treatment on the ultra-high-strength steel blank through a composite phosphate solution to obtain A layer of high temperature resistant composite lithium iron phosphate-calcium sulfate film is used to improve the life of the mold. Background technique [0002] At present, the application of metal surface treatment by phosphating solution is very wide. In the early 20th century, due to the invention of tool steel and metal surface phosphating technology, the extrusion of ferrous metals was realized. The extrusion of ferrous metals was first used in military industry. The most typical product is the bullet casing. In the 1950s, the extrusion of ferrous metals began to be used for civilian use, and is currently widely used in t...

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Problems solved by technology

In recent years, the emerging hot stamping forming technology can realize the quenching heat treatment of the sheet while forming, improve the formability of the material, and greatly expand the application range of high-strength ultra-high-strength steel in auto parts. For ultra-high-strength heat For stamping, the general temperature is slightly lower than the ultra-high-strength recrystallization temperature. For example, the hot stamping of steel is generally above 900°C. At this time, the phosphating layer is destroyed and satisfactory lubrication cannot be obtained during the stamping process, which greatly reduces the mold life span