Powder metallurgy originated in more than 3000 BC.The first method of making iron was essentially powder metallurgy.
1) there are always pores in the product;
2) the strength of ordinary powder metallurgy products is lower than the corresponding forgings or castings (about 20%~30% lower);
3) Because the fluidity of the powder in the forming process is far less than that of the liquid metal, the structure and shape of the product is limited to a certain extent;
4) the pressure required for forming is high, so the products are limited by the capacity of pressing equipment;
5) the high cost of pressing die, generally only applicable to batch or mass production.
Metal powder: the quality of the final product is difficult to control freely;Metal powder is expensive;Powder does not comply with the law of hydraulics, so that the shape of the product structure has a certain limit.