Performance Requirements for Welding Safety Shoes

Performance Requirements for Welding Safety Shoes

In metallurgy, shipbuilding, construction, and other industries, welding operations are very common, and the welding operation environment is generally harsh. The flame, arc, hot weldment, splashing metal droplets, red-hot electrode tip, and slag in the welding process are the main heat sources that cause welding burn accidents; and some materials must be preheated before welding. Heat, the preheating temperature can reach 150 ~ 300 ℃; in addition, during the electric welding operation, there are also many opportunities to contact electricity, such as the wrong connection between the live wire and the neutral wire caused by the fault of the electric welding equipment or line, the reverse connection of the welding transformer, and the wrong connection. High-voltage circuits, and the insulation damage between the primary winding of the welding transformer and the secondary flexible group, etc., will cause 220V and 380V voltage to appear on the secondary circuits such as welding tongs (or welding guns), workbenches, etc., so electric shock is also one of the dangers of electric welding operations. one. In summary, welding work shoes must be heat-resistant, insulating, and wear-resistant and non-slip labor protection shoes. The uppers of welding work shoes are generally made of bovine (positive, repaired, suede) leather, pig (positive, repaired, suede) leather or other natural leathers.

 

Upper leather: There are mainly positive leather, modified leather, suede, and other varieties. Pigskin, cowhide, and sheepskin are mostly used as raw materials, made of chrome tanned, generally dyed in various colors, and oiled with emulsion. Except for suede and individual unfinished leather (suede is unfinished), most of them are finished. Its thickness varies according to the requirements of different raw leather and shoemaking (between 0.5~1.8mm), and the thick upper leather without lining can reach more than 2.5mm.

 

The upper should have flame resistance, and the burning speed should not be greater than 1m/s. The combination of the upper and the bottom is formed by a molding process, the high waist style, and the foam soft leather roll opening at the top of the shoe, which is not only comfortable to wear but also protects the ankle from friction.

 

1. Technical requirements

 

1. Sole heat resistance

For low heat-resistant welding safety shoes, the heat-resistant temperature of the sole is required to be 150 ℃

For heat-resistant welding safety shoes, the sole heat-resistant temperature is required to be 250 ℃

 

The heat resistance requirement of the shoes is to place the shoes on a temperature-adjustable heating plate, and put steel balls in the shoes. Sand is then filled around the shoe to the height of the upper edge of the sole, but not above the upper. Wait for the temperature to rise to 150°C (stable for 20 minutes. Cool to room temperature, observe the sample, the shoes should not melt, deform or separate.

For heat-resistant welding safety shoes, the sole heat-resistant temperature is required to be 250 ℃

 

2. 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: under the condition of 150 ℃,  after 40 minutes, record the surface temperature of the insole every 5 minutes and then calculate (from the sample when placed on the heating plate), the average temperature is obtained, and the difference between it and the temperature of the inner surface before the test shall not exceed over 22℃

 

3. Insulation

The electrical insulation performance of welding safety shoe should withstand a voltage of 6kV, and the leakage current should not exceed 3mA.

 

4. Mechanical

The physical and mechanical properties of the sole of the welding safety shoes and the peel strength of the finished shoe meet the requirements of the standard for molded leather shoes.