Weldable Components

Manufacturing standards are governed under ANSI/ASME B 16.9. Butt-Weld Fittings are available in variety of kinds such as tees, caps, elbows, reducers and outlets.

Weldable components are used to connect pipes.

Buttweld Pipe Fitting Specification & Standards

Welded pipe fittings are made as per ASME spec B16.9. ASME B16.9 covers factory made wrought steel butwelding fittings in sizes 1/2" to 48". This standard however does not cover low pressure corrosion resistant buttwelding fittings. See MSS SP-43, Wrought Stainless Steel Butt-Welding Fittings.

A234 WPB is the most common material used for carbon steel butt welded fittings.

ASTM A234 WPB is the Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service.


Chemical Composition%

Grade C Mn P S Si Cr Mo Ni Cu Others
max max
WPB 0.3 0.29-1.06 0.05 0.058 0.1 0.4 0.15 0.4 0.4 V 0.08
(1,2,3,4,5) max min max max max max max
  1. Fittings made from bar or plate may have 0.35 max carbon.
  2. Fittings made from forgings may have 0.35 max Carbon and 0.35 max Silicon with no min.
  3. For each reduction of 0.01% below the specified Carbon maximum, an increase of 0.06% Manganese above the specified maximum will be permitted, up to a maximum of 1.35%.
  4. The sum of Copper, Nickel, Niobium, and Molybdenum shall not exceed 1.00%.
  5. The sum of Niobium and Molybdenum shall not exceed 0.32%.
Stainless Steel Butt Weld Fittings:

Stainless buttweld fittings are available in 316 and 304 grades.

304/304L (UNS S30400/S30403) 

Chemical Composition%

C Cr Mn Ni P S Si
0.035 18.0- 20.0 2.00 8.0-13.0 0.045 0.030 1.00

 Tensile Requirements

Tensile Strength:  (KSI) = 60                                      

Yield Strength:  (KSI) = 35                                          

(KSI converts to MPA {Megapascals} by multiplying by 6.895)         

316/316L (UNS S31600/S31603)  

Chemical Composition%

C Cr Mn Mo Ni P S Si
0.035 16.0- 18.0 2.00 2.0-3.0 10.0-14.0 0.045 0.030 1.00

Tensile Requirements 

ASTM A420 WPL6 pipe fittings

The ASTM A420 WPL6 steel pipe fittings means the butt welding pipe fittings whose material is ASTM A420 grade WPL6.ASTM A420 is standard specification for piping fittings of wrought carbon steel and alloy steel for low-temperature service.So A420 WPL6 fittings are specially used in low temperature conditions.

Chemical composition of A420 WPL6 material:

Grade C Mn P S Si
WPL6(1)(2) 0.3 0.60-1.35 0.035 0.04 0.15-0.30

Mechanical properties of A420 WPL6 material:

Tensile Requirements WPL6
Tensile Strength
min, ksi [MPa]
Yield Strength
min, ksi [MPa]

ASTM A420 WPL6 pipe fittings are one kind of butt welding pipe fittings,they are commonly produced from the steel pipes of ASTM A333 Grade 6.This material should be arranged the charpy V impact test in temperature of -46℃,to make sure it can work in a lower temperature service,for example in cold weather,winter or deep-sea water offshore projects.

Welded pipe fittings in carbon steel and stainless steel are the joining components that make possible the assembly of valves, pipes and equipment onto the piping system. Welded fittings compliment pipe flanges in any piping system and allows;

  1. Change direction of flow in a piping system
  2. Connect or joint pipes and equipment
  3. Provide branches, access and takeoffs for auxiliary equipment