Open Die Forgings :
Quality Assurance comprises of Chemical Analysis, Physical Testing, Metallography and Metrology. The department is equipped with facilities for Wet Chemical Analysis as well as Spectroscopic Analysis, Ultrasonic Testing Machine and Microscope.
The following steps are followed during material processing: -
1. RAW MATERIAL:
The raw material i.e. an Ingot or a Bloom from the following sources: SAIL, Alloy Steels Plant, Durgapur & SAIL, Durgapur Steel Plant ( For Industrial Forgings and Forged Rolls).The chemical analysis is done before taking the raw material into forging and if necessary, ultrasonic testing carried out in case of Blooms. Then the raw material is colour coded.
2. FORGING STAGE:
Then the raw material is forged as per the requirement of the customer while proper forging ratio is maintained. Material is heated in the furnace and is forged at the required temperature based on the chemistry of the material. Forging temperature is verified with the help of an optical pyrometer. Each forging is marked with a specific identification number and registered along with forging dimensions. A visual inspection and dimensional checking are conducted properly and then sent for further processing. Just after the material is forged, the following care is taken: -
(A) For Carbon Steel: After forging they are left to cool in the open air.
(B) For Alloy and special grade steel: The forged items are kept in a sand bath to avoid any thermal shock & to reduce the risk of the stress developed.
3. HEAT TREATMENT:
Then the forged material is subjected to normalizing or annealing according to the requisite cycle. After this, the forged item is either proof machined or remains as forged state. The necessary graph chart for this heat treatment cycle is provided to the customer.
Many times, the ingot itself is annealed for stress relieving, if required. For further heat treatment i.e. hardening and tempering, we usually send the materials with all details to our approved heat treatment unit. We provide our customer with the graph chart, details of the heat-treatment cycle and a certificate for the materials, which are heat-treated.
4. TESTS CARRIED OUT:
(a)Tensile, yield strength, elongation tests are done in Govt. approved lab only and hardness both in house & Govt. approved lab.
(b) Impact Test (in some specific cases) is conducted in Govt. approved lab.
(c) Ultrasonic Test (both in house and in Govt. approved lab).
(d) D. P. Test, Macro and Micro structure in house and in Govt. approved lab.
5. FINAL DISPATCH:
Materials are then Finish machined, if required, tested, inspected and made ready for dispatch. The identification number provided during forging stage is maintained throughout the process so that it could be traced back to the mother body and finally while dispatching the materials, we provide all the Test Certificates and Guarantee Certificate along with the materials. Further, Quality Assurance Plan provided by the customer for stage inspection is strictly followed. The tests mentioned in Serial No. 4 are also carried out in the Laboratories approved by the customer, if opted.