Glass Lubricants role in extruded seamless steel pipe

1941 SejournetJ is assisted by the grace of electric company, successfully tested glass lubricant, making the development of hot extruded steel as possible, and the rapid spread worldwide.

Traditional steel extrusion graphite (flake graphite and oil, tar or oil mixed into the paint, etc.) as a lubricant. But the disadvantage is that graphite lubricant: ` greater thermal conductivity, poor insulation, mold temperature rise of large, fast wear, long product extrusion difficult. a prone products by carbon, when squeezed prone to intergranular corrosion of stainless steel, it is necessary to remove the carburized layer after extrusion, resulting in increased metal consumption. b often cause environmental pollution.

Compared with glass graphite lubricant, its advantages are: ` glass thermal conductivity, blank surface to prevent excessive cooling, but also can play a role in protecting workers die. a has good lubricating properties, can be large extrusion ratio and improve extrusion speed, which can expand the range of products extruder. b glass lubricants, chemical stability, does not cause tissue defects. c glass lubricant can easily change ratio, to achieve different physical properties (such as softening point, viscosity, etc.), to accommodate the need for extrusion of different materials. d can be kept clean when glass is used as a lubricant. In short, glass lubricant significant advantages. Many foreign study results indicate, using glass extrusion lubricant effect the best steel.

Must be lubricated extrusion seamless steel parts are: extrusion molding, extrusion mandrel tube and three parts.(1) extrusion die lubrication: mold lubrication method commonly pressed into the frit glass mat, i.e. before pressing the glass mat is placed between the mold and the blank. In order to ensure continuous glass mat to soften the friction surface, the desired shape and mold hole inlet cone and the shape of the ends of the blank glass mat match. Glass mat extrusion cylinder diameter is generally smaller in diameter than 3 ~ 5mm. Glass mat bore diameter less than or equal to the diameter of the die hole. The thickness of the glass mat generally take 4% to 8% of the length of the blank.(2) extruder barrel and mandrel lubrication: extruder barrel and mandrel lubrication should use a low softening point, a small particle size of the glass powder coated billet inner bore and an outer surface. In addition, can also be wrapped with a glass cloth wrapped around the surface of the blank and a glass cloth wound on a mandrel method.(3) removing the steel surface of the glass film: As the time of extrusion using a glass lubricant, pressing the glass film residue having a thickness on the inner and outer surfaces of the steel pipe 20 ~ 50μm, the nature of hard and brittle, detrimental to subsequent processing and use must be removed. Clear methods include mechanical and chemical methods. Mechanical methods have shot, water and stretch straightening methods. Application of clear glass film during chemical method, due to the steel surface of residual glass lubricant has a high chemical stability, it needs to remove alkali solution or acid solution. Deficiencies pickling lies in aggressive large variety of pipe materials, pipe surface may produce excessive acid, especially a greater erosion of carbon steel, and therefore subject to restrictions on use. PH joint clearance method currently used.