You can introduce carbon into the mix in the form of cast iron. This is the easiest way to increase the carbon content of steel when melting.

Thank you so much sir

Dear Mr. Navratan Panwar,

You may add carbon to the alloy by using small pieces of graphite. I recommend putting clean graphite particles under the main charge so that during initial melting the arc does not throw the graphite particles. If you are going to use aluminium foil, you may wrap the graphite particles in the foil and then put it under the main charge in the VAR crucible. Controlling the arc current and melting time is very important since it affects the waste amounts of alloying elements during the process, specifically manganese. You probably need to remelt the ingot once or twice for better chemical homogeneity, so it is better to estimate the waste amounts of the alloying elements and consider them in the initial charge beforehand based on previous experiments in your laboratory.

I hope this helps.

Best regards,

Amir Sabet

Amir Sabet Ghorabaei Would you please let me know how we could calculate the wasting amount of elements?

Dear Mr. Reza Rashidi,

In my opinion, theoretical calculation of the loss of alloying elements during melting may not be a straightforward task due to several influencing parameters in the melting process, and experimental evaluation can be a better approach.

For estimating the loss of alloying elements, one can first melt the charge without considering any loss in the first melting attempt, during which the inert gas pressure inside the VAR melting chamber, arc current, and the active time at each selected arc current need to be recorded. The chemical composition of the ingot is then measured by a suitable method and relative loss or recovery values for different alloying elements can be calculated by using the initial and measured chemical compositions as follows:

Loss = (initial wt% of 'x' – measured wt% of 'x')/(initial wt% of 'x')

Recovery = 1 – Loss

For better precision, the ingot can be remelted (second attempt) under the same melting conditions (without considering any loss yet) and then the chemical composition is measured again. The purpose of the second attempt is to estimate the loss of alloying elements when they are all initially dissolved in the melt, the values of which are usually lower than those calculated in the first attempt.

In the final attempt and again under the same melting conditions, the chemical composition of the ingot can be fairly adjusted by adding proper amounts of wasted elements considering the calculated recovery (loss) values for each of them in the first and second attempts.

I used the above method (excluding the second attempt) to adjust the manganese concentration in a high-strength low-alloy (HSLA) steel. Although the melting method was different (vacuum induction melting [VIM]) and the loss of manganese was higher than that in the VAR method, almost the same procedures were used and the results were satisfactory.

Best regards,

Amir Sabet

Dear Amir Sabet Ghorabaei Thank you very much for your detailed answer. The production of metallic glasses with VAR requires several remeltings (at least three times to ensure chemical homogeneity, and even more if there is an oxide layer on the ingot surface). This makes loss estimation more complex. Thanks again.

There are several ways to add carbon to steel, including:

In vacuum arc melting, it is generally possible to use any of these methods to add carbon to the steel alloy. The choice of method will depend on the specific requirements of the alloy and the equipment available for the melting process. It may be helpful to consult with a metallurgist or materials engineer to determine the best approach for adding carbon to the steel alloy.