Wyniki wyszukiwania - BazTech

1

Effect of different extrusion temperature and speed on extrusion welds

Bingöl S., Keskin M. S.

Journal of Achievements in Materials and Manufacturing Engineering

|

2007

|

Vol. 23, nr 2

39-42

EN

Purpose: In this study, it is aimed to investigate the structure of seam weld and transverse weld sections comparatively. To achieve this, it is studied on an extrusion profile type which has seam weld and transverse weld regions. Design/methodology/approach: Producing extrusion profile has been performed by a press, which has a capacity of 1460 tones, in a real producing and carried out by changing the exit temperature and ram speed, which are the important parameters. Exit temperature TE, is chosen as 440, 475, 500, 520 and 560 degrees centigrade. Extrusion speed is also taken in the base of ram speed VR, and production is carried out at the speeds of 2, 4, 6, 10 and 15 mm/s. Therefore the effects of extrusion parameters on macrostructure properties have been investigated. Findings: It is seen clearly that some differences are occurred from the viewpoint of structural features between the regions, when the experimental results are observed without regarding the extrusion parameters. In addition, it was observed commonly the structure of the material had a change through re-crystallization with increasing temperatures. This situation decreases the significance of seam weld regions. But insignificancy of seam weld region is designed as possible as can be from the viewpoint of decorative. However, when the macro structural figures have been investigated as the ram speed increases more significance on seam welds occurs. Research limitations/implications: Also some macrostructural differences in extrusion welds may occur for between having the other important extrusion parameters such as pressure and extrusion ratio. Therefore, effect of the other parameters can be investigated in future. Practical implications: In application, extrusion welds occur on both solid and hollow profiles. Moreover, extrusion temperature and speed often changes. This study shows that these parameters effect to macrostructure of extrusion welds. Originality/value: In this study, it is seen that different macrostructural properties take place due to the process parameters variations and natural of extrusion method in the extrusion production.

2

Properties of seam welds produced with different extrusion parameters

Bingöl S., Keskin M. S., Bozaci A.

Archives of Materials Science and Engineering

|

2007

|

Vol. 28, nr 6

365-368

EN

Purpose: This study focuses to investigate the effects of different extrusion parameters on microstructural properties of seam (longitudinal) welds in aluminum extrusion profiles. Design/methodology/approach: To realize the study, it is studied on a hollow extrusion profile type which has seam weld zones. The experimental profile was produced in different temperatures, billet temperatures and ram speeds by a real extrusion press which has a capacity of 1460 tones. These parameters are some of the most important parameters in an extrusion process. Findings: Some structural differences are occurred between having the different extrusion parameters both seam welds and without weld regions, when the experimental results are observed. In addition, it was observed commonly the structure of the material had a change through recrystallization with increasing temperatures. This situation decreases the significance of seam weld lines. Moreover, the grain size is getting smaller with increasing ram speed as it is shown in microstructural figures. Research limitations/implications: Also some structural differences in seam welds may occur for having the other extrusion parameters without temperature and speed. But, the other extrusion parameters are not used in this study. Therefore, effect of some other important parameters such as pressure, extrusion ratio can be investigated in future. Practical implications: In application, seam welds occur on hollow profiles. This study demonstrates that some extrusion parameters effect to microstructure of seam welds. Originality/value: It is shown that different microstructural properties take place due to the process parameters variations and natural of extrusion method in the extrusion production. They cause also variations on structural features.

3

A quality problem in seam welds in aluminum extrusion

Bingöl S., Keskin M. S.

Archives of Materials Science and Engineering

|

2007

|

Vol. 28, nr 7

397-400

EN

Purpose: Seam welds occur during the hollow profile extrusion; the billet's material is divided into separate metal streams by the bridges of the die which support a mandrel, and then these metal streams are welded in welding chamber behind the bridges. When the desired conditions have not been provided, the required quality in seam welds may not occur. One of the possible reasons for this situation is a poor metal feed. In this study, an insufficient pressure problem occurring in seam welds on an aluminum extrusion profile section is investigated. Design/methodology/approach: The study was realized on a hollow extrusion profile type which has seam weld zones. The experimental profile was produced by a real extrusion press which has a capacity of 1460 tones. Findings: The poor metal feed occurring on specimen is shown by microstructural pictures. Microstructure of the main region has a homogenous appearance. In the microstructure, containing seam weld region, only a slight change was observed in seam weld region. However, there was no significant change in near of seam weld regions. This points out that there has been no metallurgical problem. Therefore, the problem is an insufficient pressure problem and this caused poor metal feeding. In the other hand, micro hardness tests are realized on seam weld region, main region and defective region's surround of specimen's section. After the micro hardness tests important differences are shown among these regions' strength. Hardness values of seam weld region were lower than the main material's hardness values, but higher than the defective region's. Practical implications: In application, seam welds occur on hollow profiles produced by aluminum extrusion. Originality/value: As a result, this study shows a quality problem in seam welds in aluminum extrusion.