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Article Small-scale resistance spot welding of austenitic stainless steels

Dear Mahesh

Thanks for your answer, could you tell me which are the softwares which are used to simulate and what it the easy one of them?

Welding of small scale parts (thickness < 0.5 mm) has its own fetures due to the two facts. Firstly, very low heat capacity. Secondly, contact resistances, the values of which are very unstable, affect strongly on the result of the process (different starting conditions give different heat generation and characteristics of the welds as a result). Nowadays, computer controled power sources has been developed. It can give welding current by any algorithm as well as take feedback. Moreover, the idea exists, that process should be divided on three stage: 

1. preheating for stabilisation of resistances

2. main stage for nugget formation

3. slow decreasing of current for decreasing stresses and martensite formation.

The study of more detailed technological features should be carried out for each specific combination of parts, taking into account their properties and phase transformations of the metal.

Dear Mikhail

Thanks for your valuable information.

According to your answer, the small scale Riestance Spot Welding can be considered as special case of traditional Riestance Spot Welding. So for the modeling of traditional spot welding the required model system is divided into three parts:

1- electric model where Maxwell's equations used to model the current density.

2- thermal model where used for transient heat transfer by using Joule heating.

3- mechanical model which is used thermal elastic plastic theory.

Do you this above model can be expanded to covered the Small Scale Riestance Spot Welding?

Thanks in advance.

Dear Raheem,

My opinion, two models should be added.

Firstly, the model of contacting surfaces taking into account the uncertainty of their properties, oxide films, etc. for more accurate prediction of heat generation. Nowadays, there are a lot of attempts of descriptions of the interaction of electrical contact surfaces have been made, the most suitable should be chosen.

Secondly, the model of phase transformation of the nugget during the cooling stage is useful, too.