In the powder metallurgy powder briqutting is as important as powder sintering.With the application and development of powder metallurgy technology,active powder processes study,explore powder briqutting theory should fit in with modality.

 

Since 1923 Walker first presented empirical formula that powder relative volume is linear to logarithm of pressing pressure in the powder pressing process,many scholars carried on a series of  research about powder pressing problems.The most famous are Huang Peiyun pressing equation method,Kawakita's equation method,Conor Pitskiy equation method and Barshin equation method.

 

 

1.Barshin equation was put forward by the former Soviet Union powder metallurgist M.I.O Barshin in 1938.It’s applicable to fragile rigid powder and medium hardness powder it’s applicable to medium pressure range,better or higher  plasticity pressure will appear deviation.

2.Conor Pitskiy equation method presented that pressing pressure is linear to compaction relative density will be better apply in the range of medium and high pressure.In the low pressure appear deviation applicable to majority powder pressing.In addition,E．F．Athy and I．Shapiro developed respectively two pressing equation which is belong to the same formula with connopizky pressing  formula.

3.Kawakita's equation method is a simple form and don’t adopt logarithmic relation nexus,it\s more suitable to low-pressure range and soft powder.Most powder pressing theory deal with powder compact as elastomer and ignore hardening influence and leave out time factor and so on,so applied range is limited.

4.Huang Peiyun pressing equation method obtained logarithmic equation of powder pressing in consider of adequately strain.This formula not only applicable to hard powder but also applicable to soft powde,not only applicable to powder pressing shaped but also applicable to powder calm pressing shaped,and applicable to die wall friction of steel mould of single action pressing.Compare with Barshin,Conor Pitskiy and Kawakita's equation method,HuangPeiyun logarithmic pressing’s linear equation conformity is the best,its correlation index R of regression line is the nearest to 1.