INDUSTRY RESOURCES

  • PERIODIC TABLE OF ELEMENTS
  • PHYSICAL PROPERTIES OF SOME METALS
  • CONVERSION TABLES
  • WELDING & THERMAL SPRAY INFORMATION
  • Pta Welding, Metal Spray and Thermal Spray Information

    Base Metal
    Preheat Temp.
    Postheat
       
    Low Carbon Steel (up to 0. 04%C) for thin sections only
    Not Required
    Not Required
    Air-Cool
    Low Carbon Steel (up to 0.40%C) for thick sections only
    High Carbon Steel (up to 0.40%C) for thin sections only
    Low Alloy Steels (up to 10% alloy) for thick sections only
    200-600
    93-315
    Slow-Cool
    High Carbon Steels (over 0.40%) for thick sections only
    Low Alloy Steel (up 10% Alloy) for thick sections only
    300-600
    148-315
    Slow-Cool
    Air-Quench Steels
    1100-1200
    593-648
    Slow-Cool
    High Chromium-Nickel (Austenitic) Stainless Steel
    (304, 309, 316, etc) thin sections only
    Not Required
    Not Required
    Air-Cool
    High Chromium-Nickel (Austenitic) Stainless Steel
    (304, 309, 316, etc) thck sections only
    200-500
    93-260
    Slow-Cool
    High Chromium-Nickel (Austenitic) Stainless Steel
    (410, 416, 430, etc) thick sections only
    400-600
    204-315
    Maintain at
    400' - 600' F for 4 hrs. per 1 inch thickness, then reduce heat 50'F (10'C) till cool
    High Chromium-Nickel (Austenitic) Stainless Steel
    (430, 442, 446, etc) thick sections only
    200-600
    93-315
    Maintain at
    200' - 600' F for 4 hrs. per 1 inch thickness, then reduce heat 50'F (10'C) till cool

    High Temperature Nickel Alloy
    (400, 600, 601, 718 etc)

    200-500
    93-260
    Stress-Relieve
    ....................................................................................................................................................................
    General
    Good results are often achieved by tilting the component up at an angle of just under 30’C and hard facing over the full width of the surface.

    Large areas
    When building up large areas it is advisable to divide the work into small sections and to weld in alternative positions so that heat concentrations and heat contraction stresses are not cumulative. Preparation should be so designed as to avoid any direct shear across the weld junction. A radius preparation is preferable to bevels and sharp corners, especially in the case of shear plates. Where large areas have to be built up, some measure of restraint should be taken to prevent distortion.

    Thickness of deposit
    As a general rule, it is advisable to avoid thick deposits of hard facing alloys since they are unable to accommodate the considerable shrinkage stresses set up and spalling of the deposit is liable to occur. To minimize the effects of dilution of the weld, a buffer layer is essential when welding on to materials high in carbon or alloy additions. For this purpose, a nickel-based electrode is used on cast iron, while a basic mild steel or austenitic stainless steel electrode is use on high tensile steels.



    Heavy deposits

    When a heavy deposit has to be built up with multiple runs of a weld metal, and in cases where service conditions impose impact loading on the past under repair, it is advisable to introduce a buffer layer between the hard facing and the base metal. The electrode chosen for this buffer should give a hardness value somewhere between that of the base metal and that of the final deposit. When an extreme hard face is deposited on top of a soft metal base it is often advisable to apply a layer of weld metal which gives an intermediate semi-hard deposit. The buffer layer can also be made up of layers of increasing hardness so as to form a gradual transition from the soft base metal to the wear acing layer.

    ....................................................................................................................................................................
    Machining
    In general, deposits giving a hardness below 350 HV (35HRC) can be machined with the normal tools. Deposits exceeding this hardness figure required finish. In special cases, it may be desirable to soften by heat-treatment and to reharden after machining.

    Grinding
    Grinding should be carried out with care in order to avoid cracking of the weld due to the excessive generation of heat.


    ....................................................................................................................................................................

    Process
    [mm]
    Current
    [A]
    Voltage
    [V]
    Melting Rate
    [kg/h]
    Oxy-Acetylene
    -powder
    -rod
    -
    3-8
    -
    -

    -
    -

    0,2-1
    <2kg
    Standard Electrode
    4
    5
    180
    250
    24
    25
    1,62
    2,01
    High Performance Electrode
    4
    5
    240
    350
    25
    26
    2,97
    4,30
    Solid Wire
    1,2
    1,6
    150-300
    200-390
    23-30
    25-33
    2, 2/5
    3/5,5
    Cored Wire
    1,2
    2,4
    2,8
    3,2
    150-300
    240-400
    270-450
    300-500
    25-29
    26-31
    26-31
    26-31
    3/6,5
    4/7,5
    5/9, 5
    6/11
    PTA
    50-400
    20-50
    0,5-20
     
    Ra
    (µm)
    Rt
    (µm)
    Rz
    (µm)
    RMS
    (µin.)
    CLA
    (µin.)
    PVA
    (µin.)
    0.025
    0.05
    0.06
    0.08
    0.1
    0.12
    0.16
    0.2
    0.25
    0.31
    0.4
    0.5
    0.63
    0.8
    1
    1.25
    1.6

    0.2
    0.3
    0.5
    0.6
    0.8
    1
    1.25
    1.5
    2
    2.5
    3.2
    4
    5
    6.3
    8
    10
    12.5

    0.16
    0.32
    0.38
    0.5
    0.63
    0.75
    1
    1.25
    1.6
    2
    2.5
    3.2
    4
    5
    6.3
    8
    10

    1.12
    2.2
    2.7
    3.6
    4.5
    5.3
    7.1
    9
    11.2
    14
    18
    22.4
    28
    35.5
    45
    56
    71

    1
    2
    2.4
    3.2
    4
    5
    6.3
    8
    10
    12.5
    16
    20
    25
    31.5
    40
    50
    63

    6.3
    12
    16
    20
    25
    32
    40
    50
    63
    80
    100
    125
    160
    200
    250
    320
    400
     
    Guide Roll
    0.6 - 1.0 Ra
    Center Roll
    0.5 - 0.8 Ra
    Press Roll
    0.8 - 1.2 Ra
    Touch Roll
    0.8 - 1.2 Ra
    Size Press Roll
    0.6 - 1.0 Ra
    Applicator Roll
    0.5 - 0.8 Ra
    Calender Roll
    0.1 - 0.5 Ra
    Wire Roll
    1.2 - 2.6 Ra
    Suction Roll
    1.2 - 2.6 Ra
    Yankee Roll
    0.04 - 0.08 Ra

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