論説
テーパーカップ試験による大変形時の鍛造用潤滑剤の評価
2005 年 76 巻 2 号 p. 79-86
詳細
2005 年 76 巻 2 号 p. 79-86
A lubricant plays an important part in forging, which can reduce forging load and make knockout smoothly. Ring compression test or spike test have been well used as standard evaluation methods of lubricants. However, forging conditions of parts such as flange bolt and CVJ components are much severe than those of spike test or ring compression test. So the development of more sever evaluation method of the lubricants has been desired strongly. We have developed new evaluation test by backward extrusion with taper punch. The new test named "Taper cup test" can evaluate lubrication under large deformation, which are twice ∼4 times as large as that of spike test. In this test, surface expansion ratio can be controlled by changing the punch stroke, and it is possible to know the forging limit of the lubricant by measuring the changing point of the forging load.
