Details on the Level of Lifting Chain
Ⅰ. Grade of lifting chain
When you buy lifting tools, the manufacturers introduce the lifting chain as a professional 80-level chain. In fact, there are three main levels of lifting chains.
1. High-strength type I 80: Among the 80-level lifting chain riggings, the high-strength type I system is the most widely used.
2. High-strength type Ⅱ grade 80: This type of lifting chain is not as widely used as type Ⅰ, and only chains and accessories with the same chain ring diameter and rated load can be connected together.
3. Super-strength grade 100: Compared with grade 80 lifting chains, the biggest advantage of this chain grade is that under the same diameter, the rated load is 25% higher, and the surface has higher hardness and better toughness; in addition, in terms of color on the surface, it is also different from the 80-grade chain. This kind of chain and its structural parts are all turquoise.
Ⅱ. Lifting chain forging standard
The grade of the hand-drawn lifting chain should meet the requirements of the industry standards GB4829 and GB5802. The design and manufacture of its component short chain should meet the requirements of GB4829, and its material should be killed steel smelted in an open hearth, electric furnace or oxygen top-blown converter. The steel should have good cold bendability, weldability, and not easy to produce strain aging brittleness.
Ⅲ. The breaking force and total ultimate elongation of the lifting chain
The breaking load of the lifting chain is related to the safety of the operation, and its determination should also be in accordance with the regulations in the GB4829 standard. Generally, the breaking load of a high-quality product lifting chain should be more than 4 times the rated working load. Before leaving the factory, the chain should also be tested with a tensile force of 2.5 times the rated load.