THE CHANGE OF MECHANICAL PROPERTIES IN COLD DRAWN BARS BY HEAT TREATMENT

Manufacturing methods and the applied heat treatment are important for the properties of materials. Building safe constructions with the materials used depends on the knowledge and correct use of their properties. In this study, cold drawn bar specimens of Ç1040 are heat treated in three different temperatures (500 o C, 650 o C, 840 o C) and the strength, hardness, and strain values are compared with those of untreated materials. Cold drawn bars has shown higher strength values when compared with the hot rolled bars. This is because of the type of process selected for manufacturing. By heat treatment, strain has increased, hardness and strength have decreased. It has been observed that the rate of increasing or decreasing depends on the temperature and duration of the heat treatment.

SOÐUK ÇEKME ÇUBUKLARINDA ISIL GgLEMLERLE MEKANGK ÖZELLGKLERGN DEÐGgGMG

Malzemelerin özelliklerinde, imalat usulleri ve yapýlan ýsýl iþlemler önemli olmaktadýr. Makine konstrüksiyonunda, kullanýlan malzemelerle emniyetli konstrüksiyon oluþturmak, bu özelliklerin bilinmesi ve doðru kullanýlmasýna baðlýdýr. Bu çalýþmada; soðuk çekme çubuklarýndan Ç1040 numunesine, üç farklý sýcaklýkta (500 o C, 650 o C, 840 o C) ýsýl iþlem uygulanmýþ ve ýsýl iþlem uygulanmamýþ ( 25 o C’deki ) numunelerle mukavemet, sertlik ve % uzama deðerleri karþýlaþtýrýlmýþtýr. Soðuk çekme çubuklarý, sýcak haddelenmiþ çubuklara oranla daha fazla mukavemet deðerleri göstermiþtir. Bunun sebebi imalatta seçilen iþlem türüdür. Isýl iþlem ile sertlik, mukavemet deðerleri azalmýþ, süneklik (% uzama deðerleri) artmýþtýr. Artýþ ve azalýþ oranýnýn, uygulanan ýsýl iþlem sýcaklýðýna göre deðiþtiði görülmüþtür.