How to purchase iron castings and rough casting from China
(experiences and problems)

Many purchasers were failed to buy their iron castings in China. Why? I think there are two aspects of factors. One is because of iron casting suppliers in China. Another is because of the problems of purchasers.

Herein, I will not talk about the problems of suppliers, I just hope to give some advices to purchasers and remind some problems happened during purchasing activities.

I think the purchasers for iron castings and steel castings should notice the following issues:

1. rough weights of iron castings

The price of iron castings is strictly based on the rough weights of iron castings, or called raw weights of castings. Rough weights are very important. The suppliers usually hope to take the rough weights of samples as the base of quotations. So, as a purchaser, you should clearly denoted the machined weights or rough weights on the drawings. If you do not know the accurate weights, you should tell the suppliers, and ask the suppliers to calculate or estimate the weights of the rough castings.
Many purchasers may think the weights are the issues that suppliers should consider, not their consideration. This is wrong idea. If the suppliers can not make an accurate quotation, the result of purchasing must not be satisfying.

2. key requirements to materials

As the purchasers, you should denote the material grades on the drawing or in your requirements. Moreover, if you have special requirements to chemical components, hardness or strength. You should tell suppliers clearly.

3. detailed requirements to machining

The purchasers should denote the machining requirements clearly on the drawings, including the machining positions, machining tolerance, surface smooth finish etc.

4. the tolerance of rough casting

The tolerance of rough casting will be important for suppliers to choose the suitable casting process. If suppliers choose the unsuitable casting process, the loss will be the both of suppliers and purchasers.

5. special requirements to surface coatings

Surface coatings include painting, anti-rust oil, galvanize etc. Different coatings will cause the different prices.

6. special requirement to heat treatment

Heat treatment will reduce the internal stress, improve the inside quality of ductile iron castings, or enhance the surface hardness of castings. Since the heat treatment will cause extra costs, so purchasers should tell the suppliers in the first place.

All in all, as a purchaser for iron and steel castings, you should make these requirements clear in the first place, then carefully check the quotations of suppliers to find out if the suppliers have understood and considered all requirements.

By the way, please do not always choose the lowest offer, you should choose the supplier who have considered all the requirements with a reasonable price.

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