Pulsed dc welding, Mechanical Engineering

Assignment Help:

Pulsed DC Welding

Pulsed DC involves the repetitive variation in arc current from a background (low) value to a peak value. Adjustments of the pulse current time, background current time,peak current level & background current level can be made to provide a current output wave form suited to a fixed application. Generally, pulse frequencies are ranges  from 0.5 to 20 pulses per second. Pulsed DC is usually applied with the negative electrode (DCEN). In pulsed DC welding, the pulse current level is typically set at 2 to 10 times the background  level of current. This combines the driving, forceful arc characteristics of high current with the low heat input of low current. The pulse current achieves good fusion and penetration, while the background current maintains the arc and allows the weld area to cool.


There are several advantages of pulsed current. For a given average current level, greater penetration can be obtained than with steady current, which is useful on metals sensitive to heat input and minimises distortion. Very thin metals can be joined with pulsed DC. In addition, one set of welding variables can be used on a joint in every positions, like  circumferential weld In a horizontal pipe. Pulsed DC is also useful for bridging gaps in open root joints. 


Related Discussions:- Pulsed dc welding

Illustrate the general shear failure in bearing capacity, Illustrate the ge...

Illustrate the general shear failure in bearing capacity. General Shear Failure: In this case of failure, contiguous failure surfaces develop between the edges of the footin

Molding methods according to the method of making a mold, Q. Molding method...

Q. Molding methods according to the method of making a mold? Following are the molding methods according to the method of mold making: • Open mold method: the method is su

What are the limitations of reversed carnot cycle, (a) What are the limitat...

(a) What are the limitations of Reversed Carnot Cycle to be used in practice for refrigeration purposes? Also derive the mathematical expression of COP for reversed carnot cycle.

Air-gas cross-limiting and air-gas ratio control, Q. Air-Gas Cross-Limiting...

Q. Air-Gas Cross-Limiting and Air-Gas Ratio Control? The Steam Generator firing demand signal is directed to two discrete signal selectors. A low signal selector ensures that

Value of the maximum shear stress , Value of the maximum shear stress: ...

Value of the maximum shear stress: Illustrates that for a given maximum shear stress the minimum diameter needed for a solid circular shaft to transmit P kW at N rpm may be ex

Wrought al alloys, Wrought Al Alloys This aluminium alloys are acquir...

Wrought Al Alloys This aluminium alloys are acquired by addition of Mn and Mg. The Al-Mn and Al-Mg alloys cannot be heat treated. Al-Mn alloy combines high ductility along wi

Dynamic analysis., dynamic analysis of four bar linkage by kelin''s constru...

dynamic analysis of four bar linkage by kelin''s construction.

Resultant of non-coplanar force system, Resultant of Non-coplanar Force Sys...

Resultant of Non-coplanar Force System: The resultant of a system of coplanar forces can be attained by adding up two forces through law of parallelogram at a time and after t

Compressors, How can I construct a tyre pumping machine.

How can I construct a tyre pumping machine.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd