Welded safety shoes must be heat-resistant, insulated, and wear-resistant, non-slip labor safety shoes.
Why are welded safety shoes so demanding on materials? Because the flame, arc, hot welds, splashed metal droplets, red hot electrode head and slag in the welding process are the main heat sources for welding burn accidents, and some materials must be welded to the weldments before welding. Preheating, preheating temperature can reach 150 ~ 300 °C; In addition, there are many opportunities to contact electricity during electric welding operation, such as the misconnection of the live wire and the neutral wire caused by the failure of the welding equipment or the line, the welding transformer is reversed, misconnected Into the high-voltage circuit, as well as the insulation damage between the primary winding of the welding transformer and the secondary flexing group, etc., will cause 220V, 380V voltage to appear on the secondary circuit of the welding tongs (or welding torch), workbench, etc., so the electric shock is also the danger of electric welding operation. one.
Welded safety shoes need to have heat resistance, heat insulation, insulation and mechanical properties.
1, heat resistance
Low-heat-resistant welding safety shoes require a heat-resistant temperature of 150 °C ± 5 °C. High-heat-resistant welding safety shoes require a heat-resistant temperature of 250 °C ± 5 °C. The heat resistance of the shoe is to place the shoe on a heated plate of adjustable temperature, and the shoe is filled with steel balls. The sand is then placed around the shoe and the height of the sand reaches the upper edge of the shoe, but does not exceed the upper. Wait for the temperature to rise to 150 ° C ± 5 ° C, stable for 20 minutes. Cool to room temperature and observe the sample. The shoe should not melt, deform or separate.
2, heat insulation
Welding safety shoes require good thermal insulation. The midsole of the shoe should be a material with good insulation. The test equipment is the same as the heat resistance test. The experimental method is: at 150 ° C ± 5 ° C, after 40 minutes, every 5 minutes to record the surface temperature of the insole, and then calculate (from the time the sample is placed on the heating plate) the average temperature, and test The difference between the front and inner temperatures shall not exceed 22 °C.
3, insulation
The electrical insulation performance of welded safety shoes is consistent with the requirements of GB12011-89 insulated shoes. The withstand voltage is 6kV and the leakage current does not exceed 3mA.
4, mechanical properties
The physical and mechanical properties of the welded safety shoe sole and the peel strength of the finished shoe meet the requirements of the standard for molded shoes (QB1005-90).
Welding safety shoes are also widely used in gas cutting, gas welding, electric welding and other welding operations.