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AR-MAX®

AR-MAX® - Nickel Alloy Armor Plate
AR-MAX® is produced to rigid specifications in electric furnaces, vacuum degassed,
quenched and tempered into a unique high strength alloy steel made for a combination
of ultra high strength and toughness. High Nickel content insures through hardness.
AR-MAX is designed for applications where both abrasion and/or impact resistance are
major considerations.


AR-MAX® - Technical Summary

Hardness Range: 444 - 532 BHN (nominal)
Forms: Plate (custom forms and fabrications available)
Std Sizes (W x L): 48x96, 72x240, 72x288, 96x240, 96x288
Thickness: 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1 1/4, 1 1/2, 2, 2 1/2, 3
ASTM: Exceeds A578 Level 1


Nickel Alloy Armor Plate Grade Steel Ar-Max Chemistry Chart


AR-MAX® - Approved Welding Rod and Wire

1.AWS E7018 usually acceptable as an all purpose rod to join AR-MAX® to itself or most low alloy steels. An AR-MAX® weldment will produce desired dilution with the electrode to enhance greater strength at joint.

2.AWS E8018, E9018, E11018, E12018 all are examples of low hydrogen electrodes which may be used to weld AR-MAX®. To further enhance strength at weld joint, E11018-M can be applied.

3.AWS E309 or E310 are recommended when joining AR-MAX® with either 11-14% austenitic manganese or stainless steels.



AR-MAX® - Recommended Material Processing

Torch Cutting
Conventional gas cutting procedures are satisfactory. Some hardening along the cut edges may occur. A small volume of heated metals at the edge is usually controlled by cold metal next to it which incurs limited restraint. Preheating the plate to 300° F - 350° F before flame cutting can decrease stresses.

Forming
AR-MAX® has been bend tested using a 6" dia. pin. 1/2" through 1" thick coupons were used for both longitudinal and transverse tests.
 
Thickness         Bend Radius
Through 1/2"          6t
over 1/2" to 1"        3t

If the bend is parallel to rolling direction of plate, radii should be increased. “Bumping” in a press brake is recommended procedure for forming heavier sections. Care should be exercised to insure that brake equipment has capacity to bend form hardened steels, usually
4x power required to form mild steel. Some representative values on actual cold bending are listed below.
 
Thickness         Min. Radius
   1/4"                        6"
   1/2"                       12"
   3/4"                       18"
     1"                        24"
  1-1/4"                     30"

Machining
Standard high speed drill bits may be used on AR-MAX® at full hardness with some modifications.
(a) Included angle should be approximately 140°.
(b) Grind lip to a 5° positive rake with a .031 inches land width.
(c) To reduce pressure and work hardening, reduce web to approximately .090 inches.
(d) Cutting speeds of 4-6 SFM and feeds of .004-.005 inches per revolution are recommended for standard high speed drills.
(e) With cobalt or similar grades of high speed drills, cutting speeds of 8-10 SFM can be used.
(f) Positive power feed is essential to provide a continuous chip and minimize work hardening. Tools should be kept sharp, otherwise a tendency for friction build-up will occur which will impede further machining.
(g) For countersinking, use same feed and speed as for drilling. Four or six flute tool recommended.


Welding
Consumables:

1. AWS E7018 usually acceptable as an all purpose rod to join AR-MAX® to itself or most low alloy steels. An AR-MAX® weldment will produce desired dilution with the electrode to enhance greater strength at joint.

2. AWS E8018, E9018, E11018, E12018 all are examples of low hydrogen electrodes which may be used to weld AR-MAX®. To further enhance strength at weld joint, E11018-M can be applied.



3. AWS E309 or E310 are recommended when joining AR-MAX® with either 11-14% austenitic manganese or stainless steels.

Joint Design and Techniques:

1.Choose weld joint design, weld location and the sequence of assembly of members by welding which will minimize weld restraint.


2.Choose the weld joint design and contour the weld finish to minimize zones of stress concentration. Butt welds are preferable to fillet welds. Remove backing strips if used, and then back weld. Metal Removal Any of several methods may be used if it is necessary to remove welds, or portions of welds or base metal, such as in back gouging, correction of errors and removal of defects. Arc-air gouging followed be cleanup grinding is suggested. Proper air pressures and currents generally minimize carbon deposits which may occur in arc-air gouging. Grinding to 1/32 inch below the exposed surface will normally remove any carbon deposits. If arc-air gouging and clean-up grinding are not done properly, carbon deposits on the exposed surface may subsequently cause cracking. Chipping, grinding or machining are other suitable methods for metal removal. Caution: Do not use an oxyacetylene torch for gouging since the heat input by this method is difficult to control and excessive heat input may result in a detrimental reduction of mechanical properties for the base metal of the weld joint.

Nickel Alloy Armor Plate Grade Steel Ar-Max Plate Thickness Preheat Interpass

(a) Applicable to shielded metal arc, gas metal-arc, fluxcored-arc and gas tungsten-arc welding processes.
(b) A preheat or interpass temperature above the minimum shown may be required for highly restrained welds; however, preheat or interpass temperature should not exceed 400° F for thicknesses up to and including 11/2 in. 450° F for thicknesses over 11/2 in.
(c) Welding a steel which is at an initial temperature below 100° F may require localized preheating to remove moisture from the surface of the steel.
Weld Finish Refinements in design, workmanship, and inspection are necessary because welding joints in AR-MAX® alloy are usually loaded to higher stresses than are joints in steels of lower strength. Abrupt changes in section should be avoided. Offset in alignment of sections to be butt welded should be minimized. Any such offset should be faired at three-to-one taper over the width of the finished weld. The maximum weld reinforcement should not exceed 10 percent of the material thickness of 1/8 inch, whichever is less. The junction between the face of a weld and the base metals should merge smoothly into the base metal with minimum undercutting for fillet welds and groove welds, as well as for butt welds. The face of such welds should be free of coarse ripples, grooves, overlaps, abrupt ridges or valleys. Welding techniques used must be such as to provide adequate weld penetration, particularly at the root.



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