High Performance Stainless Steels
NASS 45® Bushing Stock – (450 Stainless mod.) Non-Galling
Stainless Bushing Stock
• NACE MR-01-75-97 revision
• High Mechanical Strength
• Excellent Corrosion Resitance
• Double Stress Relieved
• Machinable – Not Gummy
• High and Low Temperature Service
To maintain the unusually high degree of toughness, service temperature should be limited to approx. 800°F, although Nass 45 exhibits excellent oxidation resistance to 1200°F.
* Rough machined with allowance for proper clean-up.
- Wear Rings
- Hex Nuts
General Machining Data
Use high speed tools.
Turning Single Point, and box 70/90SFPM IPR .015/.007. Turning and cut-off, 70SFPM IPR .0015
Drilling: (1/4" Diameter SFPM50, IPR.004); (3/4" Diameter SFPM70, IPR.0015)
Milling: Cut-depth .050" SFPM85 IPR.001 to .004. TAP SFPM 12 to 2
General Welding Information
Nass 45 has a grain structure of tempered martensite, and a blended alloy composition that is favorable for welding without preheating. In most instances this alloy may be used "as welded", requiring no post weld heat treatment (PWHT).
The solidification mechanisms of Nass 45 are the same as those of standard austenitic stainless steels, such as 304 and 316. Therefore the welding characteristics and approach should follow that typical to standard austenitic stainless steels. The use of certified welders, and adherence to the sound welding practices and precautions, recommended for the welding of standard austenitic grades, should always be observed.
Nass 45 welds superior to austenitic grades because the carbon content is generally lower than the standard austenitic grades. Ductility at the weld, however, is somewhat less than austenitic grades. A root pass with a highly ductile rod, such as a 308L, should be considered to minimize fracture potential where stress raisers, such as the undercut on a partial penetration weld, might present a potential crack initiation site. The weld may then be completed by use of a higher strength heat treatable filler metal. Type 630 filler wires and covered electrodes closely match the Nass 45 base metal composition. (AMS-5763)
Where high strength is not a requirement, welds may be completed using only the 308L type rod. Use of this rod offers the most forgiving approach in maintenance field weld conditions. This type of weld is less susceptible to hydrogen embrittlement. Items in this category may be used in the as-welded condition. (If welding to dissimilar materials, consideration should be given to use of a more highly alloyed rod, such as a 309 stainless, or Inconel type rod. Arc welding, gas-tungsten arc, gas-metal arc, and shielded metal arc welding processes, have all been used successfully for joining Nass 45, although gas-tungsten arc welds appear to be the most favored for greater weld metal cleanliness, highest ductility and toughness, especially following any post weld heat treatment. Maintain shortest arc. Where maintaining strength properties closest to the original properties of Nass45 is important, a post weld heat treatment (PWHT) of 1150°F for 4 hours should be employed.
Mill Treatment: (as produced 30RC typical)
Solution annealed at 1900°F for 7 hours. Aged at 1150°F for 4 hours. Double stress relieved. Note: Thermal treatment of Nass 45 is different than 17-4 on the length of time for the soak. 17-4 type of material requires only 1 hour. Nass 45 requires 4 hours.
To re-harden Nass 45 from H1150 (30RC) to H900 (36 to 47RC):
Nass 45 is a modified 17-4/15-5 type of PH (precipitation hardening) stainless steel. The modifications consist of elements such as Moly, Silicon, Copper, Columbium, etc., combined with unique processing techniques. Thermal treatment of this product, however, remains similar to the standard solution treatment of a non-modified 17-4PH type base metal. Furnace heat the bar to 1,875°F to 1,925°F, hold 1 hour at temperature. Rapidly air- cool to room temperature. (May be oil quenched to room temperature if preferred). Re-heat to 900°F. Hold at temperature for 4 hours. Let material cool to room temperature. Note: Time at temperature is the same regardless of whether it is a 1-1/2"Diameter or at 4"Diameter.