Mar-10 is a vacuum remelt grade of martensitic age-hardenable stainless steel, custom-designed for pump-shaft type applications which require higher strengths than type 304, 316/317 stainless steels, and greater corrosion resistance than type 410/416, or 17-4PH stainless steels (CEVM ASTM-A-565-92A). MAR-10 also meets aircraft industry specifications: (SAE/Aerospace Materials Specification) AMS 5773. In addition, MAR-10 is specially ground and polished, straightened to pump shaft requirements, and crated for protection. MAR-10 is the premium age-hardening stainless grade of pump shaft in the market.
Benefits of Mar-10
Corrosion Resistance: MAR-10 resists atmospheric corrosion, including salt water atmospheres, equal to type 304 stainless and, in many cases, equal to 316 stainless steel. Because of the various factors affecting corrosion, predictive abilities are limited. Please consult a Baldwin representative with your specific application.
Heat Resistance: Maintains physical properties in high heat service up to 900°F. With some applications, it may perform at even higher temperatures. Excellent oxidation resistance up to 1200°F.
Galling Resistance: Excellent resistance to galling. Exceeds commercial stainless grades, including 18-8 stainless.
Wear Resistance: MAR-10 provides excellent wear resistance, yet remains machinable.
Fatigue Resistance: High degree of toughness provides excellent resistance to fatigue failures.
Compare Mar-10 to 410/416/316 SS
316 Stainless is most often selected for its ability to resist corrosive attack. In heavy industrial maintenance applications however, it would be very unusual to find an application where the problem was just limited to corrosion.
Often the failure of shafting is the result of several influences: corrosion, twist, chatter, stress, wear, flex, etc. The unique properties of Mar-10 resist failure where any or all of those conditions exist.
When you consider that 316 Stainless:
- Can be mushy to machine
- Does not wear as well
- Has much lower strength levels (i.e. tensile)
- Is harder to weld
- Is susceptible to stress corrosion cracking
- May invite galling
- Can cause premature wear on the mechanical seals due to flex
In areas where types 410 and 416 Stainless have been utilized, Mar-10 should also be considered.
410 Stainless is most often selected because it is hardenable and weldable, but it is difficult to machine.
416 Stainless is most often selected because it is hardenable and easy to machine, but welding is not recommended.
Mar-10 provides greater resistance to corrosion. Even 410 and 416 do not resist Atmospheric Pitting as well as Mar-10. As delivered Mar-10 provides an unusual degree of toughness, is easy to machine, and is weldable.
Consider the savings with Mar-10 in not only the extended service life but also in the replacement of three materials in inventory with just one.
Common Applications of Mar-10
Mar-10 Size Range
|1 1/8||2 15/16|
|1 1/4||3 1/8|
|1 5/16||3 3/16|
|1 3/8||3 7/16|
|1 7/16||3 1/2|
|1 1/2||3 3/4|
|1 9/16||3 15/16|
|1 11/16||4 7/16|
|1 3/4||4 1/2|
|1 13/16||4 15/16|
|1 15/16||5 1/2|
|2 1/8||6 1/2|
Properties of Mar-10
Typical Mechanical Properties (2″ rd. at 70 degrees)
|% of elongation||0.18|
|Reduction in area||0.5|
|Charpy V notch impact||60 ft. lbs.|
Furnished in a ductile hardened condition. Further hardening generally not required.
Note: Mar-10 represents a balance of corrosion resistant and abrasion resistant properties. As the hardness range is adjusted, the balance of these properties will be affected. Consult a Baldwin representative before you alter hardness.
Use standard good welding practice for chrome, nickel, stainless steel (i.e. fusion or resistance weld). Insure surface is clean; weld so as to cause minimum heat input (e.g. stringer beads, rapid travel, smallest diameter electrode or wire, etc.).
Machining and Chemical Data for Mar-10
Maintain positive cut to minimize work hardening. Use carbide tools with liberal oil coolant (80/90 SFPM). Minimize vibration and chatter. Cold form, hot work or machine as other age-hardened martensitic grades.