Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : formability


Numerical and Experimental Explorations for the Formability of Drawing Square Cups Through Deep Drawing Operation (January 2020)

Nareen H. Obaeed

Engineering and Technology Journal, 2020, Volume 38, Issue 9, Pages 1316-1326
DOI: 10.30684/etj.v38i9A.1340

This study aims to examine the formability of drawing cups having square shapes through direct deep drawing process on a single action press through one pass. This can be accomplished by conducting an FE simulation and performing an experimental investigation on steel substrate type AISI 1008 blank with diameter and thickness dimensions 80, 0.5 mm respectively. To explore and analyze the formability of such a drawing process, two process parameters have been included in this work which is the speed of punch (30 and 300 mm/min) and the lubrication state (with machine oil and dry drawing). Both direct and indirect measurements of thickness strain have been adopted as an indicator of the sheet formability. The results of both FE simulation and experimental work demonstrate that the square drawing of the AISI sheet has been accomplished for all the four cups produced since the highest thinning over the cup wall does not exceed 25% of the original thickness. Generally, there is a good match between the experimental values of the indirect method and the FEM results for all models such that the largest deviation is about 25%. The direct method of thickness measurement is determined to be non-confident as strain values are practically unacceptable. Additionally, higher formability of the sheet has been realized at lower punch speeds. Furthermore, no significant difference has been observed in the formability at both speeds of punch when using a lubricant compared to the dry drawing operation.

The Formability and Elongation of Aluminum Alloys AA5083 and AA3003 for Micro-Truss Sandwiches Manufacturing

Arwa F. Tawfeeq; Matthew R. Barnett

Engineering and Technology Journal, 2020, Volume 38, Issue 9, Pages 1396-1405
DOI: 10.30684/etj.v38i9A.556

The development in the manufacturing of micro-truss structures has demonstrated the effectiveness of brazing for assembling these sandwiches, which opens new opportunities for cost-effective and high-quality truss manufacturing. An evolving idea in micro-truss manufacturing is the possibility of forming these structures in different shapes with the aid of elevated temperature. This work investigates the formability and elongation of aluminum alloy sheets typically used for micro-truss manufacturing, namely AA5083 and AA3003. Tensile tests were performed at a temperature in the range of 25-500 ○C and strain rate in the range of 2x10-4 -10-2 s-1. The results showed that the clad layer in AA3003 exhibited an insignificant effect on the formability and elongation of AA3003. The formability of the two alloys was improved significantly with values of m as high as 0.4 and 0.13 for AA5083 and AA3003 at 500 °C. While the elongation of both AA5083 and AA3003 was improved at a higher temperature, the elongation of AA5083 was inversely related to strain rate. It was concluded that the higher the temperature is the better the formability and elongation of the two alloys but at the expense of work hardening. This suggests a trade-off situation between formability and strength.

Effects of Process Parameters in Incremental Sheet Metal Forming Using Visioplasticity Method

Abdul Jabar Moqdad Abdul Jabar; Karem M.Younis

Engineering and Technology Journal, 2016, Volume 34, Issue 12, Pages 2334-2346

Single point incremental forming SPIF is a flexible manufacturing process that does not require a special die for each part and is conducted on CNC milling machine that control on the motion of the forming tool. The formability is very important in any forming process therefore this work is concentrated on the influence of some factors on formability during SPIF. The factors that were studied are: type of tool path, depth step, feed rate and tool rotational speed. Three factors (depth step, feed rate and tool rotational speed) are examined depending on three levels (low, medium and high levels) while the type of the tool path was examined depending on two levels (low and high levels). In this work the total number of experiments is 18 experiments except the screening experiments that were made beforethe main experimental tests. Response surface method is used to build the predictive model to predict the value of effective strain for experiments that are not experimentally conducted. The results show that the feed rate and interaction between step size and type of tool path have the largest effect on formability. It is found that the maximum value of formability in terms of effective strain was (ε ̅=0.5049) while the minimum value was (ε ̅=0.26456). It is also found that SPIF is affected by the friction at the interface between forming tool and sheet metal as in other metal forming processes.

Study of Factors Affecting on Formability of Stainless Steel Alloys

Math Ahmed Abdulallah; Hassan Baker Rahmetallah; Samier Ali Alrbii

Engineering and Technology Journal, 2010, Volume 28, Issue 1, Pages 84-102

Factors affecting on formability of austenitic stainless steel AISI321 and two
duplex stainless steels GOST A917, and SAF2205, have been studied in the asreceived
condition at different strain rates, testing temperatures, and directions.
The mechanical properties obtained from tensile testing (strength, ductility, strain
hardening index, and strain rate sensitivity), have been chosen as criteria to detect
the formability. The values of these criteria are compared with stretching behavior
obtained from Olsen test (peak height, maximum stretching force, and total work
done). Strain hardening index, elongation, and tensile: yield ratio, were found
good criteria which represent formability. Results from tensile and stretching tests
of these alloys in the as-received condition, showed that the austenitic stainless
steel had the best formability due to its higher ductility and work hardenability.
Formability was found to be dependent on strain rate, testing temperature, and
rolling direction due to the anisotropy. Stretching tests for the three alloys in the
as-received condition, showed that 321 austenitic stainless steel had higher (hvalue)
, followed by 2205 duplex. Lubrication was found to improve formability
by increasing the (h-value) for the three alloys.