Gas Welding: Gas welding up to 1800c
Electric Welding 2000c ~ 10000c.
½ “ thick plate 4000c ~ 6000c
6 “ thick plate 9000c ~ 10000c
¼” 2000c ~ 2500c
1/8” 1800c ~2000c
TIG Welding we use
Tungston Inert Gas Welding
1-We use Non consumable tungsten electrode
2-We use Argon as shielding gas
3-We weld only Ca, Al and alloys of Cu & Aluminium
MIG Welding
1-We use consumable electrode using automatic wire feeds.
2-We use MIG welding Machine to weld both Ferrous (Cu, Al and alloys)
3-For welding Al and Cu, we use Argon as shielding Gas.
4-For welding Stainless steel we use Co2 as shielding Gas.
Submerge Arc Welding
SMAW is a five pass welding or multiple pass welding powder. Arc dips into flux. SMAW is a single pass welding. SAW welding powder flux is used properties.
1-Zero defect welding
2-Zero distortion
3-High efficiency
4-Able to weld high volume after work Submarines, Tanks, Ships, Pressure Vessels ( Having Lange thickness)
5-Single pass cutting
What is Earthquake Resistance Steel?
These following qualities should be in steel:-
1-Elongation should be 20%
2-Should be Galvanized ( coating)
3-Should be retain -20c to +20c
Note:- ( 95% defects in welding due to materials)
What is soaking time?
During this period we heated the metal called (soaking time).
What is Radiographic?
Through this we can see all defects, flaws and cracks.
Posted by: Adnan
Wednesday, January 14, 2009
Chalpy Law:-
Chalpy Law:-
Chalpy impact test is done to check if toughness of the metal is same from +40c up to -40c and from + 40 to -40c if metal is tough it will be remain 50% ductile and 50% brittle. Usually metals which are used in fabrication of Air craft and low temperature service application its notch toughness must be same from +40 to -40c. Normally low alloy steel especially Nickle steel has good notch toughness even at -250c to such Nickle steel. Nickle steel with 36% Nickle has good notch toughness even at -300c.
This Nickle is used to make pressure vessel for storage of Hydrogen and Helium having boiling points below -250c . (-350c solidity).
Notch toughness only Alloy steel has good notch toughness where as plain has inferior.
Vanadium: Vanadium makes metal shock metal and also improves notch toughness.
For high temperature: Moly.
Tungsten: Tungsten is added in steel to improve toughness at high temperature like moly.
Ultra high strength steel:
Ultra high strength steel has more than three alloying elements. Like these following mentioned:
V: Vanadium
W:Tungsten
Co: Cobalt
Ni: Nickle
Posted by: Adnan
Chalpy impact test is done to check if toughness of the metal is same from +40c up to -40c and from + 40 to -40c if metal is tough it will be remain 50% ductile and 50% brittle. Usually metals which are used in fabrication of Air craft and low temperature service application its notch toughness must be same from +40 to -40c. Normally low alloy steel especially Nickle steel has good notch toughness even at -250c to such Nickle steel. Nickle steel with 36% Nickle has good notch toughness even at -300c.
This Nickle is used to make pressure vessel for storage of Hydrogen and Helium having boiling points below -250c . (-350c solidity).
Notch toughness only Alloy steel has good notch toughness where as plain has inferior.
Vanadium: Vanadium makes metal shock metal and also improves notch toughness.
For high temperature: Moly.
Tungsten: Tungsten is added in steel to improve toughness at high temperature like moly.
Ultra high strength steel:
Ultra high strength steel has more than three alloying elements. Like these following mentioned:
V: Vanadium
W:Tungsten
Co: Cobalt
Ni: Nickle
Posted by: Adnan
Cold Work Steel
Cold work steel:
Cold work steel is Dye Steel (D1, D2, D3, D4, D5………. Etc.
Carbon = 2% + Vanadium, Tungsten, Nickle, Silicon……. High strength
Cold working (Room Temperature)
Hot work steel:
Hot worked steel is used to make hot working dies for receiving Malten metals for casting.
Hot worked steels series H1, H2, H5, H11, H13, H14 etc.
Carbon = 2%
Moly, Vanadium, Tungsten, Nickle, Silicon
Moly and Tungsten are High temperature.
Hot working (High temperature)
Note: (Greater the Number of alloying elements in steel with 2% carbon higher is the Hardening Temperature / Normalizing temperature).
Posted by: Adnan
Cold work steel is Dye Steel (D1, D2, D3, D4, D5………. Etc.
Carbon = 2% + Vanadium, Tungsten, Nickle, Silicon……. High strength
Cold working (Room Temperature)
Hot work steel:
Hot worked steel is used to make hot working dies for receiving Malten metals for casting.
Hot worked steels series H1, H2, H5, H11, H13, H14 etc.
Carbon = 2%
Moly, Vanadium, Tungsten, Nickle, Silicon
Moly and Tungsten are High temperature.
Hot working (High temperature)
Note: (Greater the Number of alloying elements in steel with 2% carbon higher is the Hardening Temperature / Normalizing temperature).
Posted by: Adnan
Flux Composition
Types of Cracks in Weld:
1.Hydrogen Cracks or Cold Cracks or delayed Cracks.
2.Hot Cracks or Sulphur or Phosphorous Cracks.
Flux Composition:
1: Mn + S Mns ( Slag) Removal of S&P to reduce Hot cracks in weld
2: Mn + P Mnp (Slag)
4.Na + H NaH ( Slag) ( Removal of Hydrogen to reduce Hydrogen Cracks.
5.Ca + H CaH ( Slag)
6.K + H KH
7.Si + O2 SiO2 (Removal of oxygen to reduce stress corrosion cracks in weld.
Posted by: Adnan
1.Hydrogen Cracks or Cold Cracks or delayed Cracks.
2.Hot Cracks or Sulphur or Phosphorous Cracks.
Flux Composition:
1: Mn + S Mns ( Slag) Removal of S&P to reduce Hot cracks in weld
2: Mn + P Mnp (Slag)
4.Na + H NaH ( Slag) ( Removal of Hydrogen to reduce Hydrogen Cracks.
5.Ca + H CaH ( Slag)
6.K + H KH
7.Si + O2 SiO2 (Removal of oxygen to reduce stress corrosion cracks in weld.
Posted by: Adnan
Welding Symbols & Residual Stress
Spot Welding:
V groove :
K groove:
X groove:
II I groove:
Flare:
K flare:
Frange:
Double frange:
Filled Weld:
Weld Bead:
Site welding:
Full circle welding:
Full circle fillet welding:
Flux ingredients take out impurities from molten pool as slag
During welding Residual stress develop in Weld Bead and Heat Affected Zone.
Residual Stress:
It is sum of all the welding stresses types.
1. Stress due to higher heat in put.
2. Stress due to higher coaling rate or rapid coaling of weld after welding.
3. Stress due to impurities and gases which enter molten pool during welding.
What is Molten Pool (when molten pool solidifies after coaling it becomes weld bead).
Posted by: Adnan
V groove :
K groove:
X groove:
II I groove:
Flare:
K flare:
Frange:
Double frange:
Filled Weld:
Weld Bead:
Site welding:
Full circle welding:
Full circle fillet welding:
Flux ingredients take out impurities from molten pool as slag
During welding Residual stress develop in Weld Bead and Heat Affected Zone.
Residual Stress:
It is sum of all the welding stresses types.
1. Stress due to higher heat in put.
2. Stress due to higher coaling rate or rapid coaling of weld after welding.
3. Stress due to impurities and gases which enter molten pool during welding.
What is Molten Pool (when molten pool solidifies after coaling it becomes weld bead).
Posted by: Adnan
Elongation Tensile Load Standard
Elongation Tensile Load Standard
Alloy steel standard before breaking: 15: 20 % (International Standard)
Pakistani steel standard: 11%
This standard has been followed by Pakistan Central Testing Laboratory update as per ASTM standards 1952 not revised with the present needs.
What is the difference between Voltage and Ampere?
Voltage: Voltage is difference of potential to do work between two points.
Current: Current is flow of electrons due to applied voltage. Life safety is to use Low Voltage & high amperage current.
Heat ( Energy) = Power
Power = V x I = VI
100 KVA
Posted by: Adnan
Alloy steel standard before breaking: 15: 20 % (International Standard)
Pakistani steel standard: 11%
This standard has been followed by Pakistan Central Testing Laboratory update as per ASTM standards 1952 not revised with the present needs.
What is the difference between Voltage and Ampere?
Voltage: Voltage is difference of potential to do work between two points.
Current: Current is flow of electrons due to applied voltage. Life safety is to use Low Voltage & high amperage current.
Heat ( Energy) = Power
Power = V x I = VI
100 KVA
Posted by: Adnan
Heat Treatment Techniques
Big cavity will allow oxygen and other gasses to enter and make it brittle. Close grain Good quality and no stress good quality 100% strength.
Close grain or close packed grain is formed due to heat treatment of metal and metal grain become soft.
Open grain: Poor quality high stress, poor ductility and highly brittle.
Over heating and very low temperature makes grain of metal brittle and loss of ductility and strength and boundry between two grains is far apart and cavity size become large.
Posted by: Adnan
Close grain or close packed grain is formed due to heat treatment of metal and metal grain become soft.
Open grain: Poor quality high stress, poor ductility and highly brittle.
Over heating and very low temperature makes grain of metal brittle and loss of ductility and strength and boundry between two grains is far apart and cavity size become large.
Posted by: Adnan
Important Temperature
Some Important temperature
Hardening Temperature Cooling process
Carbon Steel 780 – 850c Cool in Air
High Speed Steel1200 – 1250c Cool in Air
Dye Steel 900 – 1000c Cool in Air
Spring steel 780 – 850c Cool in Air
Tempering Process
Element Temperature Time
Carbon Steel 200 – 220c ½ hours
Dye steel 200 – 400c 1 hour
High speed steel560 – 600c 1.5 hours
Spring steel 300 – 350c 1-3 hours
Annealing Process
High carbon steel830 – 870c 4 hours
High Carbon steel810 – 850c 4 hours
Dye- steel 800 – 850c 4 hours
Spring steel 750 – 800c 4 hours
Normalizing Process
Carbon steel 830 – 880c Cool in air
Spring Steel 760 – 810c Cool in air
Carbon Manganese ( Tool Steel) 800 – 850c Cool in air
Metal Temperature by color
Faint Red 500c
Blood Red 580c
Dark Cherry 635c
Medium Cherry 690c
Cherry 745c
Bright Cherry 790c
Salmon 845c
Dark orange 890c
Orange 940c
Lemon 1000c
Light yellow 1080c
Posted by: Adnan
Hardening Temperature Cooling process
Carbon Steel 780 – 850c Cool in Air
High Speed Steel1200 – 1250c Cool in Air
Dye Steel 900 – 1000c Cool in Air
Spring steel 780 – 850c Cool in Air
Tempering Process
Element Temperature Time
Carbon Steel 200 – 220c ½ hours
Dye steel 200 – 400c 1 hour
High speed steel560 – 600c 1.5 hours
Spring steel 300 – 350c 1-3 hours
Annealing Process
High carbon steel830 – 870c 4 hours
High Carbon steel810 – 850c 4 hours
Dye- steel 800 – 850c 4 hours
Spring steel 750 – 800c 4 hours
Normalizing Process
Carbon steel 830 – 880c Cool in air
Spring Steel 760 – 810c Cool in air
Carbon Manganese ( Tool Steel) 800 – 850c Cool in air
Metal Temperature by color
Faint Red 500c
Blood Red 580c
Dark Cherry 635c
Medium Cherry 690c
Cherry 745c
Bright Cherry 790c
Salmon 845c
Dark orange 890c
Orange 940c
Lemon 1000c
Light yellow 1080c
Posted by: Adnan
Important Temperature
Some Important Boling Points
Element Value/Boiling Point Quantity of Nickle Statement
Butene -0.5 to -5.0c 2.5 % Low carbon steel
Ammonia -33c to -35c 2.5% Al killed steel (It kill bad affects of iron)
Propane -45c 2.5% Low alloy high tensile steel
Propylane -48c 2.5% With 2.5% Nickle addition
Co2 -79c 3.5% 3.5% Nickle
Acetylane -84c 3.5% Nickle
Ethyane -104c 3.5% 3.5% Nickle
Methane -163c 9 % 9 % Nickle
Oxygen -183c 9 % 9 % Nickle
Argon -186c 9 % 9 % Nickle
Nitrogen -196c 9 % 9 % Nickle
Hydrogen -253c 36 % 36 % Nickle
Helium -269c 36 % 36 % Nickle
Posted by : Adnan
Element Value/Boiling Point Quantity of Nickle Statement
Butene -0.5 to -5.0c 2.5 % Low carbon steel
Ammonia -33c to -35c 2.5% Al killed steel (It kill bad affects of iron)
Propane -45c 2.5% Low alloy high tensile steel
Propylane -48c 2.5% With 2.5% Nickle addition
Co2 -79c 3.5% 3.5% Nickle
Acetylane -84c 3.5% Nickle
Ethyane -104c 3.5% 3.5% Nickle
Methane -163c 9 % 9 % Nickle
Oxygen -183c 9 % 9 % Nickle
Argon -186c 9 % 9 % Nickle
Nitrogen -196c 9 % 9 % Nickle
Hydrogen -253c 36 % 36 % Nickle
Helium -269c 36 % 36 % Nickle
Posted by : Adnan
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