Quality Control

Pattern Making / Methoding

On receipt of Purchase order, job card is prepared & thereafter methoding-Runner, Riser and construction of pattern is decided looking to the intricacy and quality so required, whether wooden or Metallic patterns & match plate designs etc. Lay out is being carried out for radius curvature, assembly match etc. and the sample casting is cast.

Incoming Raw Material Check

Incoming raw material like Sand/Foundry Fluxes, Additives, M.S. Scrap & Basic Ferro Alloys along with virgin metals are checked on Spectro/Lab. Foundry Fluxes are being procured as per our standards requirement, with Batch Nos. and Test Reports which is essential so as to achieve quality castings.

Chemical Check

Each and every heats are being checked on Spectro prior to Tap of heats.

Test Bars : As per our customers requirement and material specification, test bars being cast integrally or separately for checking hardness, tensile testing etc.

Melting

This is being done by standard Melting practice adopted by the foundries. Every Heat Scrap is accurately weighed with the addition of Ferro Alloys, which are required as per chemistry to maintain the ratio for achieving the results. To ensure quality results, every heat is checked with the Tempmaster for Temperature before Tap on FERROLAB-III thereby sample prior to tap is obtained for Spectro analysis, which takes about 5 seconds for report and thereafter metal if okayed, is tapped & and poured in the moulds.

Every Heat tapped will correspond to Heat No. marked on casting if require and can be cross-checked with T.C.

Moulding

Moulding is done by Pneumatic ramming process, i.e. by hand moulding or machine moulding. We also have installed high pressure moulding machine 2 nos -type FOROMAT 20-1 imported from Germany. Moulding process is being decided whether moulds to be prepared from Green Sand or CO2 sand process / Nobake , depending upon the items to be manufactured. Sand is prepared with the help of sand Mills. Binding material is to be added like Bentonite, Dextrine, Sodium Silicate, Molasses etc. After sand is prepared, sand sample is tested on our Lab. for compressive strength, Permeability etc.

In moulding as well as in core making special sand is required which depends on intricacy of casting / heavy casting, i.e. Olivine, Chromite, Zircon sand etc.

Knock off / Heat Treatment

After casting is poured given suitable time for cooling, knock out is carried out on the knock out Machine by way of which casting is separated from the mould box. Sand is conveyed back by conveyor system automatically to Hopper for re-use.

From the knock our machine rough castings are lifted by crane and runner, risers are cut off from the casting with Gas Cutting / Arch cutting. Then through chipping, sand is removed from slots/holes. Thereafter it goes for heat treatment which is done as per the specific requirements. They are normalized, Stress relieved or water quenched/air quenched. H/T Furnace temperature is fully controlled by PID controllers are further managed by supervisors and Auto Programmer's.

Sample Inspection

Before we release the item for bulk production sample inspection on casting is required to be checked for the dimension, Machining allowances as per drawing & for the quality. Whether runner, riser provided as per requirement. If not, then methoding to be changed with joint discussion & for further improvements, change if any incorporated or put on job Card's to follow there upon.

In Process Control

In process control like chemical composition, Moulding quality or any foundry defects, these are checked by our quality department. (Moud Hardness, finish etc.)

Fettling / Shot Blasting

After the casting are heat treated, taken for fettling by swing Grinders/Hand Grinders so as to achieve smooth surface finish. Shot blasting is being done, If required as per client's requirement.

Final Inspection/Marking/Gauges

(A) Dimensional Inspection : Each and every casting dimensions are checked with the help of measuring instruments & Gauges duly certified. Assembling with mark nos. are to be mentioned, so that there will be no fitment problem.

(B) Dye Penetration Test :This test is carried out for checking the surface defects. This is being done at random 5 to 10% of lot required by clients.

(C) Physical Testing : As per the specification physical testing like hardness, bend test, tensile testing is being carried out on UTS machine which is yearly calibrated by LLOYD'S.

(D) Ultrasonic/X-ray testing / Microstructure : This will be done if specified in the P.O. and quality requirement charges extra will be indicated during Enquiry/ Order Finalization.

(E) Marking : Our monogram 'NAB' is cast on each every casting.