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Flat Bar AR 400

Impact AR400 Flat Bar

CMC Impact Metals AR400 is a purpose-treated steel for use in construction, manufacturing and structural applications. Heat treating steel increases the steel’s abrasion resistance while keeping weight low. Impact AR400 flat bar is used as wear strips, for abrasion-resistance and where higher strength and toughness is needed. This product is developed for use in repetitive movement applications such as manufacturing, bulk material handling, paper, pulp and steel mills.

Low alloy steel flats, heat treated to a nominal hardness of 400 HBW. Product is intended for use in applications requiring a combination of high abrasion resistance and weldability.


Flat Bar Grades of Abrasion Resistant 400*

1" - 6" 1/4" - 1" 20' Impact AR400
8", 10", 12" 3/8" - 1" 20'  

*Please inquire about other merchant products such as channels and beams, and other sizes not listed above.


Mechanical Properties

  • Surface hardness 360-440 HBW (aim 400 HBW)
  • Mechanical testing methods in accordance with ASTM A370, latest revision
  • Material tested per heat, per size, and per heat treat lot


Chemical Composition

  C Mn P S Si Cu Ni Cr Mo CE* Max CE typical
Max 0.28 1.50 0.04 0.04 0.35 0.35 0.25 0.70 0.25 0.70 0.61-0.64

*Carbon Equivalency calculated using the following formula: C.E. = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

Standard Dimensional Tolerance

Cross-sectional dimensions Per ASTM A6, table 26
Length Per ASTM A6, table 30
Straightness 1/8 inch in 5 FT maximum deviation

Machining, Cutting, Fabrication and Welding*

Impact AR400 Flat Bars are more challenging to drill, machine and punch compared to as-rolled steel due to increased hardness and strength levels, but can be successfully accomplished with appropriate tools. Carbide tipped tools are recommended, but high speed steel tools can be used provided hardness is 54–55 HRC (540 – 560 HBW) minimum and adequate cooling is provided. Compared to as-rolled high strength grades (50-80 KSI), slightly lower speeds and higher pressures are recommended for proper chip formation.

Free bending should be performed utilizing maximum allowable bend radius to prevent cracking.

Impact AR400 Flat Bars can be welded by conventional processes such as SMAW, SAW and GMAW provided that the weld procedures used are suitable for this grade and design of the welded structure. Proper weld procedures should include the following:

  1. Low Hydrogen conditions must be used.
  2. Excessive preheating (>350 F) should be avoided to prevent softening.
  3. Slow cooling rates should be avoided to prevent low toughness in the HAZ.
*These statements are general guidelines. CMC Impact Metals is not responsible for the results of any welding work performed.

CMTR Information Provided

  • Heat number and chemical analysis of all elements listed from ladle analysis
  • Brinell hardness value per heat/thickness/heat treat lot
  • Additional testing available upon request

Please inquire about other merchant products such as channels, beams and other sizes not listed above.

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