REXALLOY®™ GRADE 33
Wear, Corrosion Resistant Parts & Cutting Tools
REXALLOY®™ is a proprietary trademark of Alloy Cast Products, Inc. (73779483) U.S.A
Abrasion and Wear Resistance:
Conventional indentation hardness tests or Rockwell tests do not generally determine the relative wear resistance of REXALLOY®™ as compared with other materials such as tool steels. High carbon-high chrome tool steels commonly used for maximum resistance to abrasion or wear can be heat treated to about 64 Rockwell C (885 VPN). REXALLOY®™ , for non-cutting applications, has a hardness of about 54 Rockwell C (654 VPN). However, the hardness of the individual micro-constituents gives an entirely different picture:
The primary carbides in REXALLOY®™ are much harder than the large carbides in high carbon-high chrome tool steel, 1810 VPN as compared to 1390 VPN, although the matrix in REXALLOY®™ is softer, 488 VPN as compared to 840 VPN. Thus, the conventional Rockwell tests provide an average hardness which mask the effect of hard and soft constituents in a CAST heterogeneous alloy of this type. It is the large surface area of massive primary high-hardness carbides which produces the wear resistant quality of REXALLOY®™ .
TABER Wear Test Results
The samples were tested to 10,000 cycles with a 1000 gram load – 500 grams on each wheel. The abrading wheel was H-1O calibrade, a wheel designed for alloys resistant to abrasion.
After 10,000 cycles, results as follows:
|REXALLOY®™ 33||Milligrams Lost||Wear Factor||Hardness|
|4" x 4" x 1/8" Sample||28.3||2.83||56|
Resistance to Scaling:
REXALLOY®™ has considerable resistance to oxidation and scaling. During heating no visible oxide film is formed until the temperature exceeds 9001Ú4 F. Scaling tests indicate that REXALLOY®™ has a scale resistance comparable to Rezistal 310 at temperatures up to 20001Ú4 F.
Forming and Heat Treatment:
REXALLOY®™ 33 cannot be formed in any way by hot or cold working and does not respond to heat treatment. Its high hardness is obtained in the AS-CAST condition, and is not appreciably affected by heating at temperatures up to 20001Ú4 F. However, heating REXALLOY®™ cutting tools at temperatures above 1600 F causes a gradual reduction in their cutting life over time.
REXALLOY®™ is generally finished by grinding. Any soft wheel, not coarser than 46 or finer than 60 in Grade “X” or “J”, is suitable for machine-grinding REXALLOY®™ . Light feeds should be taken to avoid heat checking. REXALLOY®™ tools should not be quenched during grinding.
|REXALLOY ®™ 33||(AIM)|
|BALANCE CONFIDENTIAL (2.75%)|
REQUEST A QUOTE
The lower-hardness type of REXALLOY®™ for non-cutting applications can be machined with tungsten carbide tools. All types of REXALLOY®™ castings are being successfully turned with several grades of carbide tools at a surface speed of 25-40 feet/minute, a feed of .003″/revolution and a cutting depth of .010/.020 inches without coolant. REXALLOY®™ can be drilled or reamed with masonry-type carbide drills using slow speeds fine feeds and a coolant.
REXALLOY®™ is most satisfactorily joined to steel or other REXALLOY®™ parts by brazing. It is never recommended to attempt to weld REXALLOY®™ . Silver solder and a paste flux are recommended for brazing. The essentials of the process consist of grinding and cleaning the face, applying the flux, inserting the brazing strip between the faces binding the parts together with Nichrome wire, heating carefully to 13501Ú4F to 14501Ú4 F and applying pressure as the brazed solidifies on cooling.
(Handy and Harman’s Handy Flux and Easy Flo #3 (carbide type) are recommended)
- Standard Tool Bits
- Wood Working Tools
- Valve, Valve Seats
- Balls Valves
- Tipped Tools
- Reamer Blades
- Hot Extrusion Dies
- Forming Tools
- Plug Gages
- Wear Liners
- Wear Bushings
- Seal Rings
- Milling Cutter Blades
- Cut-off Blades
- Indicator Anvils
- Roller Guides
- Wire Guides
- Extreme Service Gears
- Wear Strips
- Work Rests
- High Pressure Pump Valves
- Food Processing Valves
Tools for Cutting Applications 55 to 63 Rockwell C
Parts for Non-Cutting Applications 50 to 57 Rockwell C
- 50,000-60,000 PSI
- Average range provided is not guaranteed.
- Material is not sought after for it’s tensile strength.
Elevated Temperature Hardness:
REXALLOY ®™ has a high degree of red hardness. The comparison between REXALLOY ®™ and hardened Rex AA, 18-4-1, high speed steel is shown in the following tabulations:
Hardness at temperature — BHN
18-4-1 High Speed
|Temperature 1Ú4F||Rex AA||REXALLOY®™|
Comments: Converted to BHN from Impact Brinell at temperature. On cooling to room temperature, REXALLOY ®™ attains its original hardness.
|Modulus of Elasticity — psi||35,300,000|
|Specific Electrical Resistance Room Temperature — Michrohms/cu. in.||39.8|
|Specific Heat BTU/lb./1Ú4F||0.093|
|Thermal Conductivity (Room Temperature) Btu./hr./sq. ft./1Ú4F/ft||4.8|
|Mean Coefficient of Thermal Expansion-linear Range|
|85- 5001Ú4 F||6.37 x 10-(6) in./in./1Ú4F|
|Magnetic Permeability at 200 Oersteds||1.004|
General Corrosion Resistance:
The next important property of REXALLOY®™ is its superior resistance to corrosion. In laboratory tests, standard REXALLOY®™ 33 was found to be resistant to the following:
|REXALLOY®™||0.18 - 0.20|
|XCR Valve Steel||4.30 - 4.40|
On the other hand, REXALLOY®™ is not satisfactorily resistant to 2% Hydrochloric Acid at 15001Ú4 F, nor to boiling 65% Nitric Acid.
Thus REXALLOY®™ successfully resists corrosion by moist atmosphere salt spray, the milder acids and certain of the stronger acids and alkalies. When the use of REXALLOY®™ in highly corrosive media other than those listed above is contemplated, specific inquiry is recommended, and testing should be done for your proposed application.
Lead Oxide Corrosion Resistance:
REXALLOY®™ has excellent resistance to lead oxide corrosion as shown by the following comparison:
Lead Oxide Corrosion at 17001Ú4 F, Weight Loss — grams/sq. in./hr.
|REXALLOY®™||0.18 - 0.20|
|XCR Valve Steel||4.30 - 4.40|