
MAN-CRO® Abrasion Resistant Steel Plate
MAN-CRO® 400F, 450F AND 500F
MAN-CRO AR grades are premium quality alloy steels designed to provide the greatest combination of hardness, abrasion resistance, toughness, weldability and formability.
By desulphurizing and degassing during manufacturing, we are able to offer a “clean” alloy. This process provides good cold forming characteristics and impact properties to temperatures as low as -40°F, while still maintaining good weldability. High pressure water spray-quench ensures maximum scale removal and enhances welding processes.

Available Stock Sizes
Plates | |||
---|---|---|---|
GRADE | Thickness | Width | Lengths |
MAN-CRO 400F | 3/16″ to 3″ | 48″ to 96″ | up to 288″ |
MAN-CRO 450F | 1/4″ to 3″ | 48″ to 96″ | up to 288″ |
MAN-CRO 500F | 1/4″ to 3″ | 48″ to 96″ | up to 288″ |
Bars | |||
GRADE | Thickness | Width | Lengths |
MAN-CRO 400F | 1/4″ to 2″ | 1″ to 12″ | up to 288″ |
MAN-CRO 450F | Custom Cut | ||
MAN-CRO 500F | Custom Cut |
Advantages
- Maximum Abrasion & Impact Resistance
- Excellent Weldability
- Cold Formability
- Excellent Charpy Impact Properties
- Nickel Alloy Provides Deeper Hardening
- Flat Surface
- “Clean” Steel
- Demagnetization Available
- St. Lawrence Custom Fabrication Available
- Fine Grain Structure
- Made in USA

Chemistry (typical %)
Manufactured in Compliance with ISO 9002 ABS-QE
GRADE | C | Si | Mn | P | S | Cr | Ni | Mo | B |
---|---|---|---|---|---|---|---|---|---|
MAN-CRO 400F | .12-.20 | .35-.55 | 1.55* | .025* | .015* | .55* | 1.0* | .55* | .0005-.005 |
MAN-CRO 450F | .20-.25 | .35-.55 | 1.55* | .025* | .015* | .55* | 1.0* | .65* | .0005-.005 |
MAN-CRO 500F | .25-.31 | .35-.55 | 1.55* | .025* | .015* | .75* | 1.5* | .65* | .0005-.005 |
*max %
Steel Plate Comparison
Product | Abrasion Resistance | Impact Resistance | Weldability | Machinability | Forming | Cutting |
---|---|---|---|---|---|---|
MAN-CRO 400F | G | VG | VG | F | G | VG |
MAN-CRO 450F | G - VG | G | G | M - F | F - G | G - VG |
MAN-CRO 500F | VG | F | F | M | F | G |
AR-Max | VG | VG | VG | F | G | VG |
Ultra-Met Standard | E | G | E(1) | M(2) | F | G(4) |
Ultra-Met Impact | VG | G - VG | E(1) | M(2) | M - F | G(4) |
Ultra-Met Abrasion | E - S | G | E(1) | M(2) | F | G(4) |
Hardlite | E | G | E(1) | M(2) | F | G(4) |
SLS 14% Manganese | F | E | VG(3) | M | G | G |
S: Superior, E: Excellent, VG: Very Good, G: Good, F: Fair, M: Marginal
(1) Carbon Base Only
(2) EDM, Plasma or Air Arc holes only
(3) When welding Manganese to any other metal, use 309 or 310 SS electrode w/ minimum heat input
(4) Plasma, waterjet or laser
FABRICATION
We recommend the use of St. Lawrence’s fabrication services to eliminate processing and fabrication errors.
Cutting
Plasma cutting is recommended, but all MAN-CRO grades may be gas cut with conventional fuels and procedures. MAN-CRO should be cut at minimum room temperature or preferably in a preheat range of 200˚- 400˚F to prevent surface or edge cracking. If machining is required near torch cut edges, allow sufficient stock removal to get below hardened edge or preheat to 400˚F prior to flame cutting.
Forming
The low level of oxides and sulfides present in MANCRO grades provides superior bending properties. Bending force required is approximately 4X carbon steel grades. 3t (transverse) is usually the minimum radius for MAN-CRO 400F up to 3/4˝ thick plate, 6t (transverse) for MAN-CRO 450F up to 3/4˝ thick plate and 10t (transverse) for MAN-CRO 500F up to 1/2˝ thick plate.
Machining
High speed steels, cobalt or cemented carbide can be used for planing, cutting, drilling and countersinking. Reducing speeds depending on plate hardness are recommended. Use a top angle (included) of 150˚ and edge clearance of 5°-7°.
WELDING
1) GENERAL INSTRUCTIONS
MAN-CRO grades can be welded with standard low hydrogen electrodes or wire. Submerged-arc, metal-arc and gas-shielded metal-arc (TIG) are recommended. Original mechanical properties can be maintained by using low heat input methods. To insure good welding results, be sure joint is clean and use only dry consumables.
2) PREHEATING
The pre-heat and interpass temperature should be maintained throughout welding procedure. Temperature crayons are helpful in maintaining reasonably constant temperature during welding. Under severe restraint conditions, tack welding or in damp weather, increase pre-heat temperatures by 25%.
3) CONSUMABLES
Filler metal with lower tensile and yield strength are recommended in welding MAN-CRO. This type of material provides more ductility while the weld is cooling, thus reducing stress on the joint. AWS E70XX, E80XX and E90XX shielded metalarc electrodes have been successful for submerged-arc and gas metal arc wire. Low hydrogen flux is also recommended. For a butt weld, when the joint strength must be equal to that of the parent plate, electrodes equivalent to AWS E 11018 are recommended.
Preheating
Plate Thickness Range | ||
---|---|---|
GRADE | .5″ 1″ 1.5″ | 2″ 2.5″ 3″ |
MAN-CRO 400F | 60°F Min | 300°F |
MAN-CRO 450F | 60°F Min | 300°F |
MAN-CRO 500F | 300°F | 375°-425°F |
Service comparisons Abrasion test

Charpy impact properties
Test Section .5″– 2.5″ THK
