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Chain Chain provides a strong and economical solution for many mooring applications. The weight of chain is often employed to produce a catenary effect: this has the effect of dampening loads in the system and offers a restoring force for station keeping purposes. In many cases, chain is coupled with fibre or wire rope to give the best of both worlds. Sections of chain on a mooring line provide weight and wear resistance where it is most needed, while fibre sections keep weight down and improve the managability of the system.  Jeyco is the Australian agent for Zhengmao chain, produced in Jiangsu Province China to exacting international standards. One of the largest chain making factories in the world, Zhengmao can provide chain of the highest quality, as witnessed by their approval by all major classification societies and their approval to use the API monogram. The process outlined below for the manufacture of stud link chain is that used by Zhengmao. |
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Manufacturing Chain Step One  Cutting - All raw material bar stock is checked before entering the production process to ensure correct dimensional tolerance, chemical analysis and mechanical properties. The material is then cut to predetermined link lengths, depending upon chain type. |
Step Two Heating - Each link is heated electrically, via induction or resistance, using state of the art techniques and is closely controlled and monitored at all times. The forging temperature must be correct to within narrow tolerances to maximise the mechanical integrity of the link. |
Step Three Bending - Each link is bent over a mandrill specifically designed for the size and type of chain being manufactured. Link dimensions and alignment are checked regularly to verify the accuracy of the tooling. |
Step Four Welding - Each link is transferred via carousel to the flash butt welding station. There, electric current is passed through copper clamps to heat the link to specific welding temperature, ensuring maxumum penetration and welding efficiency. |
Step Five Trimming - Excess weld or 'flash' is then removed from the link by an automatic process using special chisels, creating a smooth, flush finish around the weld area. This ensures that there is no possibility that the link could foul against adjacent equipment. |
Step Six Stud Setting - Studs are placed into the link, preventing the chain from twisting or snagging. |
Step Seven Heat Treatment - Zhengmao have 5 linear heat treatment facilities, all computer controlled, with a full range of treatments inculding normalising, water quench, oil quench and 'double quench'. This treatment brings the metallurgical qualities of the chain into compliance with the required mechanical properties. |
Step Eight Tensile Testing - Every link of chain is tested on one of three linear test beds, with a maximum capacity of 20,000 kiloNewtons. A well equipped laboratory also carries out mechanical tests during the manufacturing process, and all testing procedures are closely monitored. |
| And so the chain is complete - anything from 14mm (minimum breaking load up to 212kN) up to 152mm (minimum breaking load up to 20230kN) link diameters can be produced. |
