Effect of the parameters-spot welding, Mechanical Engineering

Assignment Help:

Effect of the parameters in spot welding

The passage of more current than what is required causes the following defects.

I. Weld expulsion
ii. Cavitations
iii. Weld cracking
iv. Reduced mechanical properties
v. Electrode embedment in the surface

On the other hand, less current results in:

i. Requirement of oversized electrodes.
ii. Reduction in the weld properties.
iii. Unfused interface.

Higher pressure causes

A. Lowering of contact resistance and hence less heat generated.

B. High distortion as against the following defects due to less pressure:

  • Pitting
  • Reduction in electrode life.

 

C. Expulsion of metal from within the weld along with more weld time results in:

  • boiling
  • porosity
  • plastic contact surfaces
  • growth of nugget up to electrode faces.

 

The uniformity of the weld depends on the cleanliness of the surface.

Rough estimates of parameters are given by hand books for different materials and thicknesses. Based on these values trials can be conducted on the welding machine available in order to fix the exact parameters, as the parameters vary slightly from machine to machine in the case of resistance welding.

When two plates of two different thicknesses are to be welded, the weld nugget grows towards the thicker side. When two plates of different electrical conductivities are resistance welded, the weld nugget grows towards the higher resistivity side. In the above two cases, the upper and lower electrodes of different diameters, are to be chosen.


Related Discussions:- Effect of the parameters-spot welding

Evaluate the specific enthalpy - thermodynamics, Evaluate the specific enth...

Evaluate the specific enthalpy - thermodynamics: Steam is being generated in a boiler at a pressure of 15.25 bar. Calculate the specific enthalpy when ( i )  Steam i

Compute the maximum efficiency of the solar cell, The main objective is to ...

The main objective is to compute the maximum efficiency of the solar cell panels, produce hydrogen and estimate the hydrogen production rate using solar cells and electrolyzer and

Virtual work, state principle of virtual work

state principle of virtual work

Derive a regression forecasting equation, Derive a regression forecasting e...

Derive a regression forecasting equation: The general manager of a company producing road rollers is convinced that the demand for road rollers is associated to the number of

Surface modeling, SURFACE MODELING: The process of modeling is built m...

SURFACE MODELING: The process of modeling is built much easier for a mathematical description of an object or at least on a part of the object might be applied. Surfaces might

Vibration, A bump/impact test is a simple technique used to determine a str...

A bump/impact test is a simple technique used to determine a structure’s natural frequency. Sketch a typical time wave response curve of such a test, then label the impact point an

Machine elements, instant center of direct contact slider

instant center of direct contact slider

Evaluate the shaft diameter, The shaft, as given in Figure is driven by pul...

The shaft, as given in Figure is driven by pulley B from an electric motor. Another belt drive from pulley A is operating a compressor. The belt tensions for pulley A are 1500 N an

Determine the maximum pressure applied inside the shell, Determine the maxi...

Determine the maximum pressure applied inside the shell: A thin spherical shell of 1.5 m diameter is built by joining steel plates of 8 mm thickness by riveting. The efficienc

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