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Our Expertise in Eutectic Welding Process
Specialist in Thermal Spraying Process
Kaizen, A trusted name for Process Cold Welding, PTA & MIG Welding Process
MAKE GRADE HARDNESS
Hoganas 1040
1060
37 to 40 HRc
58 to 62 HRc
OMG Corp. 72W40
75W62
402P
602P
37 to 40HRc
60 to 63HRc
35 to 40HRc
60 to 65HRc

And other respective grades of Nickel as well as Tungsten carbide

 
C) Inspection and Testing:
 
1. Destructive Testing:
 
A) Rockwell "C" Hardness Test for Sample Piece

A sample piece is prepared with the given base metal and specified metal powder. This piece is then machined and checked for the required surface hardness using the Rockwell "C" Hardness Tester. When the specified hardness is reached, the metal powder is then cleared for the hard facing of the jobs to be supplied to the customer.
Note : Required hardness is not possible with 0.5 mm or less coating thickness. The following table describes the hardness achievable for a given coating thickness of 0.5 mm.

POWDER COATING THICKNESS ROCKWELL - C
1040 0.5 mm 35 max.
1060 0.5 mm 50 to 55
72 W 40 0.5 mm 35 max
75 W 62 0.5 mm 50 to 55
402P 0.5 mm 33 max
602P 0.5 mm 50 to 55
 
B) Deposit Chemical Analysis
The sample piece prepared is drilled and the deposit chemical analysis is done.
 
C) Micro-etching Test

The base metal is sectioned transversely to the direction of the hard-faced overlay. The microetching test is then performed on the sectioned faces. Then the sectioned faces are visually examined with X5 magnification for cracks in the base metal and or i the heat-affected zone, lack of fusion or other linear defects, which may result in weakness or brittleness. If none of the above defected is visible then the job is cleared for further process.

 
2. Non-destructive Testing:
 
Dye Penetration Test (D.P.T.) is performed on each finished job to ensure that there is no crack or blowholes present on the hard-faced surface.
 
Acceptance Criteria : Zero Porosity, Blowholes and Cracks.
 
Hard facing procedure specification.
Process : Spray & Fuse Method.
Base Metal : ASTM A 240 Gr. 316/316L/304/304L
ASTM A 743 Gr. CF8/CF8M/CF3/CF3M.
Hard Facing Powders : Grade 1040 & 1060 of Hoganas.or
Grade 102P & 602P of OMG America.
AWS Classification of Powder : AWS A5.13 R NI Cr -A & AWS A5.13 R Ni Cr-C.
Base Metal Thickness : Min. 6mm.
Coating Thickness : Min 1mm. Max. 2mm.
 
Hard Facing by Welding Overlay :
 
Stellite (Cobalt Base Alloy) Coating with TIG Welding
   
Inspection and Testing:
 
Destructive Testing:
 
A) Rockwell "C" Hardness Test for Sample Piece

A sample piece is prepared with the given base metal and specified Bare Rod. This piece is then machined and checked for the required surface hardness using the Rockwell "C" Hardness Tester. When the specified hardness is reached, the Bar Rod is then cleared for the hard facing of the jobs to be supplied to the customer.

 
Note : Required hardness is not possible with 2.0 mm or less coating thickness.
 
B) Deposit Chemical Analysis
The sample piece prepared is drilled and the deposit chemical analysis is done.
 
C) Micro-etching Test

The base metal is sectioned transversely to the direction of the Stellited overlay. The micro-etching test is then performed on the sectioned faces. Then the sectioned faces are visually examined with X5 magnification for cracks in the base metal or in the heat-affected zone, lack of fusion or other linear defects, which may result in weakness or brittleness. If none of the above defected is visible, the job is cleared for further process.

 
Note: Destructive-testing procedure is the same for each type of Bare Rods. The following table shows the hardness achievable for a coating thickness of 3.00 mm.
BARE RODS COATING THICKNESS ROCKWELL - C
Stellite 6 3.00 mm 39 - 42
Stellite 6 3.00 mm 45 - 50
Stellite 6 3.00 mm 50 - 55

And other respective grades of Cobalt Alloy.

 
Non-destructive testing :

Dye Penetration Test (D.P.T) is performed on each finished job to ensure that there is no crack or blowholes present on the hard-faced surfaces.
Acceptance Criteria : Zero porosity, blowholes and cracks.

Preheat Temp. 200 - degree Celsius Min.
Interpass Temp. 300 - degree Celsius Max.
Shielding gas Argon
Mixtures (Gas) 99.5%
Flow 5 lit/min
Current D.C.
Polarity Positive +
Amperage 70 to 100 A
Bare Rod Size 3.16