Welding Ti-6Al-4V

 

Welding Ti-6Al-4V

 

Having mastered welding of commercially pure titanium we decided to continue our work on Ti-6Al-4V alloy of titanium which is called the work horse alloy in defence and aerospace industries.

This alloy has the following mechanical properties:

Ultimate tensile strength: 950MPa or 138kpsi

Yield strength: 880MPa or 128kpsi

Elongation: 10 to 14 percent.

These are typical values. Since Ti-6Al-4V is a heat treatable alloy the above strengths can be increased by suitable heat treatment.

For aerospace applications, the above alloy containing very low oxygen and nitrogen designated as ELI grade(Extra low interstitial) is used.

The welding of Ti-6Al-4V is not different from that of commercially pure titanium except that we used ultra pure argon gas to keep the interstitial low. Ti-6Al-4V is welded by TIG welding using commercially pure titanium filler wire or by matching composition filler wire or by the so called half alloy which is Ti-3Al-2V filler wire. The selection of wire depends upon the final property desired in the final weld.

We welded Ti-6Al-4V in annealed condition, solution annealed and solution annealed and aged condition. We also used commercially pure filler wire, matching composition filler wire and also half alloy wire. Welded test coupons were subjected to extensive testing. Test results were tabulated so that we have data bank select what type of filler wire to use for a specific application.

 

The data so collected by us was used for defence application about which I will later.

 

I was selected to establish R&D in BHPV. BHPV is established to design,manutcure and erect equipment needed for petroleum.petrochemicals, cryogenic and chemical and nuclear industreis. When a decision was taken to establish R&D, post graduate engineers from design department were transferred to form the core R&D team. We created four sections namely, chemical engineering group, cryogenic engineering group, manufcturing technolgy group and welding technology group.
Chemicl engineering group is responsible for developing computer programs for the design of equipment.
Cryogenic engineering is responsible for developing new cryogenic equipment and processes.

Timid MD 6

After the sadist left an in-house person was selected as the MD. He was a very timid person. He was afraid to take any bold decision. In the name of building consensus he used to conduct meetings and act as decided in the meeting. He was in the habit of quoting proverbs and never told any thing directly. But inspite of all these deficiancies company progressed and we managed to get some export orders. He had some personal problems which affected his decision making.
After completing his first term he managed to get a second term of five years. In the second spell he sorrounded himself with people who gave him wrong advice. He had to resign after two years. I had left the company soon after he got his second term. I learnt that during the wage negotiations with the Workers Union he was wrongly advised to agree for all their demands for the sake of harmonious relations with the Union which bankrpted the organisation. Financially company was finished and he left the Organistion a disillusioned man.

A Sadist CMD

He was the 5th CMD who joined us. He had a lot of political support at the Center which greased his way to the top post at an young age. He came from a factory and people had difficulty in recognising what product it was manufacturing. He had a shock of his life when he arrived to take charge. He had never seen such gigantic equipment beng manufactured.When he met the executives for the first time he realised that they are more experianced or more qualified than him. He hid his inadequacy by insulting even the most senior person in meetings. So much so that when he called for meetings we used to go fully ready for being insulted. He specially targetted one person who was too soft and he al;most went mad. But if someone defied him he did not know how to handle him. Technically he was incompetent and he was of the firm opinion tha welding electrodes were being coated with cowdung mixed with some chemicals! We were predominantly a welding industry welding varoius types of materials and he just could not understand why we need different types of electrodes for welding different steels! Once when I said that an equipment had developed stress corrossion cracking, he did not understand what I was talking and said"crack is in your head". He wanted me to rectify the defect in one week.When I told him that it can't be done in one week he said " if you can't do I will find some one to do it in one week." The job was so specialised that every one he asked to take the responsibility declined. Finally he called me and asked me how much time I need, I gave a time frame which he accepted tamely . In all this exercise we had lost almost a month.

Finally, he used his politcal connections to get a higher post and he left us. We all left a sigh of relief. His tenure was one of the worst period in our organisation. He destroyed the self confidence of several people

CMD from power sector

The 4th CMD was from a PSU manufacturing power boilers,turbines,condensers etc. He was trained to think big in his previous posting. Our organisation was too small for his thinking. Fortunately for him, it was a boom period and country needed to expand refineries,fertiliser plants,steel plants etc. Our company had the capacity to manufature distillation columns, storage spheres, high pressure heat exchangers, air seperation units etc.He capitalised on our strengths and liaised with the Chief Executives of refineries,fertilisers.steel plants etc. and brought huge orders. When we executed those orders our turn over jumped significantly. In a matter of few years our turnover was ten times more than what it was when joined.
He was a very nice man and taught us how to net work and how to think big.