5 Metal Structure

5 Metal Structure

1 material

The metal bearing structure materials of the sling are generally carbon steel structural steels Q235-A and Q235-B in accordance with GB700 or low alloy structural steels 16Mn and 15MnTi in accordance with GB1591.

The main bearing structure of pavers working at low temperature below -20℃ must be made of cast steel and meet the requirements of cold bending test at room temperature 180°.

Cast steel should generally comply with GB7659, GB11352 cast steel standards.

5 Metal Structure

5 Metal Structure

2 Welding joints

Major pressure assemblies of welded quality shall not be less than 1 GB3323 level Ⅱ weld or GB11345 I weld.2. Electrode, wire and flux shall be suitable for welding materials.

The electrode shall comply with GB5118;

Welds shall comply with GB985, GB986, GB10854 provisions.

2. Welding work must be carried out by qualified welders.

The welder's specification must be stamped near the weld of the principal stress member.

5. High strength bolt connection

GB/T1228 ~ 1231 should use the prescribed high strength bolts, nuts and washers, and according to the design requirements with special tools to tighten.

When cracks appear or part of the thread damage, does not reach the prescribed connection strength, should be scrapped.

4 Hinge connection

The hinge connection shall have a safety device or function that prevents the pin from disconnecting itself

2. The pins and sleeves in one of the following situations should be scrapped:

Plastic deformation;

The gap between the pin shaft and the shaft sleeve increases, which can not meet the relative motion requirements of the parts.

Pin joints wear up to 5% of the original size, should be scrapped.

5 scrap1. The main stress members are unstable as a whole.

2. The corrosion wear of the section of the main stressed members reaches 10% of the original thickness, and those that cannot be repaired should be scrapped.

3. When cracks appear in the main stressed component, measures can be taken to strengthen or change the stress distribution according to the stress and crack situation, so as to resist the crack expansion, without changing the original design performance of the component;

If it can't be repaired, it should be scrapped.

When the permanent deformation of the main force member exceeds 10% of the original state or the rod cannot work normally and safely, it should be scrapped if it cannot be repaired.

6 Major component6. A threaded fastener shall be scrapped in any of the following cases:

Plastic deformation; Crack;

D. falling teeth.