Presentation on Stellite hardfacing repair
-
Upload
gaurav-kale -
Category
Engineering
-
view
151 -
download
13
Transcript of Presentation on Stellite hardfacing repair
PROJECT ON
STELLITE HARDFACING REPAIR
ByGaurav Kale.
Sponsored Industry: KOSO INDIA, Pvt. Ltd, Nashik.
K.K. Wagh Institute of Engg. Education & Research, Nashik
Hardfacing is a metalworking process where harder or tougher material is applied to a base metal.
WHAT IS HARDFACING?
Before Hardfacing: After Hardfacing:
Hardfacing Materials:
1. Stellite:
• Grade 6
• Grade 12
Sr.No. Elements (%) Grade 6 Grade 12
1 Carbon 0.9-1.4 1.2-1.7
2 Silicon 2 1
3 Manganese 1 2
4 Phosphorous 0.016 0.016
5 Sulphur 0.015 0.015
6 Chromium 26-32 26-32
7 Nickel 3 3
8 Molybdenum 1 1
9 Iron 3 3
10 Tungsten 3-6 7-9.5
11 Cobalt Remaining (min 60%)
Remaining (min 60%)
FLAWS DURING HARDFACING:Currently the industry is facing some problems in this (Hardfacing) processes such as,
1. Cracks.
2. Porosity
3. Blowholes..
Cracks in the specimen:
Flaws overcome strategies:
Modify the present Welding Process Specification(WPS).
Suggest the new procedure according to the metallurgical properties of work piece if any.
Our Research and study:Removing flaws not possible just by
modifying the present WPS.
We found a process in which the base metal is welded first with intermediate hardness material.
• The process is known as Buffering Process.
In buffering process, the material of intermediate hardness between alloy steel and stellite is hardfaced first on valve part and then hardfacing of stellite is done.
Here, we are using stainless steel for buffering.
Buffering Process:
Specimen creation :
We are working on:
Alloy steel material: A182.
Specimen creation:Diameter : 100mmThickness:40mm
OUR OBSERVATIONS:
Stellite reacts differently with alloy steels.
Alloy steel is softer compared to cast steel
Hardfacing on alloy steel job with conventional method:
Observations for hardfacing(With convensional method):
Parameter Observations
Rotation speed meter 0.42 RPM
Powder speed 11.6 gm/min
Voltmeter 19.6 V
Ammeter 120 A
Powder gas 3.7 LPM
Center gas 2.6 LPM
Shield gas 6 LPM
Hardfacing on alloy steel specimen using
BUFFER LAYER:
Preheating the specimen:
Preheating of specimen:
Buffering process observations:
Welding process GMAW welding
Buffer Material SS 316L.
Preheat temperature 100-150℃
Interpass temperature 150℃
Current 182 A
Buffer Material:•Stainless Steel.
•Manganese Steel.
•Nickel based steel.
•Copper based steel.
Stainless steel electrode:
BUFFERING ANALYSIS:
Specimen Testing:
Hardfacing on buffered specimen:
Parameter Reading
Rotation speed meter 0.42 RPM
Powder speed 11.6 gm/min
Voltmeter reading 29 V
Ammeter reading 130A
Powder gas 4.3 LPM
Centre Gas 5LPM
Shield Gas 15LPM
Observations for Hardfacing on buffered specimen:
CONCLUSION
Sr. No. Parameter Conventional method
Modified method
1Rotation speed
meter
0.42 RPM 0.42 RPM
2Powder speed 11.6 gm/min 11.6 gm/min
3Voltmeter 19.6 V 29 V
4Ammeter 120 A 130 A
5Powder gas 3.7 LPM 4.3 LPM
6Centre Gas 2.6 LPM 5LPM
7Shield Gas 6 LPM 15LPM
Comparison Between Conversional welding and Hardfacing
after Buffering process: