ASTM A787 Tubing

A787 Type 1, 2, 3, 4 & 6

Valmont Tubing produces round electric resistance welded (ERW) metallic-coated carbon steel mechanical tubing to ASTM specifications A787 Type1 (aluminized), Type 2 (galvanized), Type 3 (hot-dip galvanized), Type 4 (galvannealed) and Type 6 (zinc-aluminum-magnesium alloy coated).  Produced in sizes ranging from 1.05 inch OD up to 12.75 inch OD and in nominal wall thicknesses beginning at 18 gauge (0.049") and heavier, Valmont's ASTM A787 tubing is used in a variety of agricultural, industrial, transportation and industrial related end uses.  For a complete listing of sizes produced, please visit our Steel Tubing Product Catalog.

A787 Type 1

ASTM A787 Type 1 welded mechanical tubing is produced using aluminized steel which is carbon steel that has been pre-coated on both sides with an aluminum silicon alloy while in coil form.  A787 Type 1 tubing is often used in applications where heat resistance and corrosion resistance are important.   

A787 Type 2

ASTM A787 Type 2 welded mechanical tubing is produced using carbon steel that has been pre-coated with a thin layer of zinc while in coil form.  A787 Type 2 tubing is often used in applications where rust resistance is critical and provides for extended durability than non-coated carbon steel. 

A787 Type 3

ASTM A787 Type 3 welded mechanical tubing is produced out of a hot rolled carbon steel and then is hot-dip galvanized per ASTM A123 specification into a tank of molten zinc after the tubing is already formed and welded.  A787 Type 3 tubing is often used in applications where rust resistance and extended durability are critical.  The hot-dip galvanizing process also allows for small batches of tubing to be galvanized at one time. 

A787 Type 4

ASTM A787 Type 4 welded mechanical tubing is produced using carbon steel that has been pre-coated with a thin layer of zinc while in coil form and then heat treated to convert the coating into a zinc-iron alloy.  The resultant coating is harder than normal galvanized and is more resistant to scratching and damage.  A787 Type 4 tubing has a matte finish and is most often used in applications where the tubing is to be painted. 

A787 Type 6

ASTM A787 Type 6 welded mechanical tubing is produced using steel that has been pre-coated with a thin layer of a zinc-aluminum-magnesium alloy coating while in coil form as specified in ASTM A1046.  Tubing produced to A787 Type 6 provides a high degree of corrosion resistance and an excellent surface appearance and is a bridge between stainless and hot-dip galvanized finishes.

Specification Notes

  • ASTM A787 covers carbon steel grades starting at 1008 up through 1021.  Please visit our Finishes & Chemistries page for a listing of our standard chemistry capabilities.
  • As a standard, Valmont applies a recoating of the weld seam area after welding for types 1, 2 and 4.  If no recoating of the weld seam is requested, please provide that information at time of quote and order placement. 
  • Physical testing (yield, tensile and elongation) is not required under A787.  If there is a specific strength requirement for your application, please be sure to include at the time of inquiry as that will affect the chemistry required. 
  • Flash control of the ID weld bead is discussed in section 7.1 to 7.1.3 of the specification.  Valmont produces tubing to flash control 0.015" maximum, 0.010" maximum, 0.005" maximum and flash in.
  • ASTM A513 is a related mechanical tubing specification that covers non-metallic coated carbon and alloy steel tubing.  Please refer to the ASTM A513 page for more information.
  • For more detailed information on the A787 specification and to purchase a copy of it, please visit the ASTM website.

Please contact one of our knowledgeable sales staff members who will assist you with any further questions regarding this specification or with your specific tubing requirements.