Quality Assurance - Karma Steels

Raw Materials : Incoming raw materials (billets or bars) are identified with color code and/or serial nos. marked on both the faces of the bars. Steels are kept separately gradewise. For a larger volume, steels are bought directly from the steel producer and chemical composition and other metallurgical properties counter checked at laboratories to confirm with the test certificates.

Surfaces are closely checked for any cracks, seams, scabs etc. These are removed by grinding, if any, and checked by dye penetrant test.

Raw Material Size	Check Testing
	Chemical Analysis	Spark Testing	Ultrasonic Testing	Grain Size, Inclusion Rating etc.
< 60 MM	25 %	Balance 75 %	Yes, if required above 32 MM Dia.	One test per lot
60-100 MM	40 %	Balance 60 %	100 %	One test per lot
> 100 MM	100 %	-	100 %	One test per lot

QAPs & Test Certificates:

Quality Assurance Plans (QAPs) are prepared and submitted to client / their inspection agencies for approval and changes, if any, are incorporated. A test certificate is submitted to the customer for every batch of supply indicating various tests carried out like chemical, physical, impact, bend, other metallurgical tests, ultrasonics, dimensional checks and co-related with supporting test certificates.
Forging Process:

a) Cut pieces of exact weight are charged in the batch type furnace and heated gradually to proper forging temperature. Intermittantly, temperatures are checked with optical pyrometer.

b) Forging is done by using best techniques and tools and undergo sufficient reduction to ensure internal soundness. If the reduction is heavy and during forging process, the temperature falls below 900 degree centigrade, the piece is again put back into the furnace for reheating. Only after attaining temperature of 1200 degree centigrade, the forging process is restarted. Sufficient care is taken to avoid excessive scalings during heating and these are removed before forging operation.

c) Mix-up in the furnace is avoided with great care by not charging same / similar sizes but different grades of materials in one batch during open forging process.

d) If required, ultrasonic testing is employed after the forging process to ensure that there are no major defects.
Heat Treatment:

The forgings are heat treated precisely as per customer's requirement. For normalising / annealing processes, 20% hardness check / batch of heat treatment is carried out. For hardening jobs, 50 to 80 % hardness check is carried out in addition to micro structure checking per batch of heat treatment. Many times, rough machining is done between annealing and hardening processes.

The test pieces, integral or separate, are heat treated alongwith the forgings and are further tested for physical, impact, bend, case depth, IGC (In case of austenitic stainless steels) as per customer's individual requirements.
Ultrasonic Testing:

Only after confirmity of physical properties, the machining operations are started. In case of requirement of ultrasonic testing (as most of open forged components), it is carried out after rough machining but before final machining avoiding closer steps, drilling, tapping, threading, taper portions etc. The procedure followed for most of the testing is as per SA 388 with DAC curves or flat bottom holes (FBH)
Finish Machining:

The various dimensions are measured with precision instruments, special guages, thread guages etc. and inspection checks are done stagewise. For bigger components, final dimensional checks are recorded individually and a copy of the same is submitted to the customer.

Quality Assurance Plan (QAP / 21)