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High Performance Stainless Steels

NASS 45® – (450 Stainless mod.) High Strength, Non-Galling,
Pump Shaft Stainless

Quit using stainless grades like 304L and 316L.

Quit using stainless grades like 410, 416 and 17-4PH.

Get rid of stainless that seizes and tears.

Get rid of stainless that "moves and walks" during machining.

Benefits and Advantages

High Strength - Nass 45 is a thermally hardened martensitic stainless alloy. It has similar strength levels to 4340 Q&T alloy bar product with approx. 140KSI tensile strength. Austenitic grades, such as 304 and 316 stainless, require strain hardening or cold reduction to obtain their hardness. As the shaft size increases, the hardness, strength, and wear resistance, drop off substantially. Nass 45 is thermally treated, the hardness and strength properties remain virtually constant, from the smallest to the largest bars.

Corrosion Resistance - Similar to that of 316L stainless, Nass 45 is engineered for use in severe service applications. Most commercial stainless grades fight corrosion but lack strength. Alloy grades and hardenable stainless grades have strength but lack corrosion resistance. Nass 45 does both.

Non-Galling - Nass 45 is non-galling. It is compatible with almost every other stainless grade, as well as carbon and alloy grades of steel. Maintenance people will find that hex nuts, caps, and collars come apart easily for inspection, replacement and repair.

Pump Shaft Straightness - Nass 45 has been specifically designed as a maintenance material suitable for pump shaft applications in highly corrosive environments. It is strong, machines easily, and stays straight during machining and in service. Nass 45 is also available with a semi-finished, oversized, surface finish, so that the size will make the size. Specify semi-finished pump shaft stock when you do not require TG&P stock.

Double Stress Relieved - Nass 45 shafts are shipped virtually free of retained stress. This material will be a welcomed change from the warp and bend, common to other stainless grades. Because Nass 45 has "low memory" properties, these shafts will not exhibit the "movement" and "walking" commonly experienced when machining 304, 316, and other stainless grades.

Typical Mechanical Properties

Hardness 258/294 BHN
Tensile Strength 140,000 P.S.I.
Yield Strength 108,000 P.S.I.
Charpy "V" Notch Impact 105 @ 70°F
Elongation in 2" 26%
Reduction of Area 65%
Machinability 50%
Micro Finish 15 RMS
(Based on 1/2" Diameter Specimen)

Agency Concurrence

• NACE MR-01-75-97 revision
• AMS-5763 (chemistry only)
• API-6A

Typical Straightness Standard

Pump Shaft Straightness = .005" in the first 5 feet, plus .0015" for each additional foot. We take extra precautions to protect small diameter bars with longer lengths but straightness is perishable.

Service Temperature

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.

High Performance Stainless Steels

Available Sizes*

1/4" 1-1/4" 2-9/16" 5"
5/16" 1-5/16" 2-11/16" 5-1/2"
3/8" 1-3/8" 2-3/4" 6"
7/16" 1-7/16" 2-15/16" 6-1/2"
1/2" 1-1/2" 3" 6-3/4"
9/16" 1-9/16" 3-1/4" 7"
5/8" 1-5/8" 3-3/8" 8"
11/16" 1-3/4" 3-7/16" 9"
3/4" 1-15/16" 3-1/2"  
7/8" 2" 3-3/4"
15/16" 2-3/16" 3-15/16"
1" 2-1/4" 4"
1-1/8" 2-7/16" 4-7/16"
1-3/16" 2-1/2" 4-1/2"

* Diameters smaller than 7/8" round may be modified due to production restrictions. Inquire on available lengths.

Typical Diameter Tolerances

Up to 1-1/2" Rd (+.000"/-.001")
Over 1-1/2" Rd to 3-1/2" Rd (+.000"/-.002")
Over 3-1/2" Rd to 4-1/2" Rd (+.000"/-.003")
Over 4-1/2" Rd to 5-1/2" Rd (+.000"/-.004")
Over 5-1/2" Rd and Above Call for details

Available Lengths

Random Bars Up To 29Ft
Custom Cut Lengths

Field Applications

  • Agitator Shafts
  • Gears
  • Pump Shafts
  • Bolts
  • Journals
  • Spindles
  • Fan Shafts
  • Line Shafts
  • Valve Stems

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.

Thermal Treatment

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.

NASS 45® vs. 300 Series Commercial Grade Stainless

Nass 45 PSQ Stainless Steel 304L & 316L Stainless Steel
Ease of machining. Engineered for ease of machining. Less induced stress. Less movement. Not gummy. Will hold a close tolerance bright surface finish. Hard to Machine. Gummy. Won't hold a bright finish. Machining difficulty results in bow and twist. Subject to bow later in service. (memory).
Corrosion Resistant. Superior service life in corrosive applications. Corrosion resistance like 316L. Corrosion Resistant. Most frequently used stainless in maintenance applications because of high degree of corrosion resistance.
High Strength. At approx. 30RC NASS 45 has Typical Tensile Properties of 140KSI - consistent from the smallest diameter through large size rounds. Low Strength. Not hardenable by heat treat- ment. Can be supplied with some hardness developed by "Strain Hardening", but limited to sizes smaller than 1-3/4" diameter. Strain hardening results in higher retained stress.
Anti-Galling. Excellent for use with OEM thread- ed parts of 300 series stainless. Use in conjunction with; 300 series stainless, 400 series stainless, PH series, carbon and alloy steel grades. Parts come apart easily during changeovers. Highly Susceptible To "Galling". Most OEM parts are supplied with both male and female parts made from a 300 series grade. Parts seize and gall. Threads are easily damaged due to galling and low strength.
Low-Retained Stress. Special "Double-Stress- Relief" at mill. Second tempering cycle added at end of mill production. Ease of machining means less stress is released during processing operations. Less stress = less memory = no movement. High Degree of Retained Stress. i.e. high degree of "Memory". Gummy during machining operations. Even moderate machining results in bow, twist, and movement.
Pump Shaft Straightness. Delivered to special straightness. (.005"in first 5 ft, plus .0015" for each additional foot of shaft.) Less wear on bearings, seals and sleeves. Shipped "Boxed-and-Cradled". Commercial Straightness. Subject to movement in machining. Subject to movement in service. Chatter, vibration, wear on bearings, seals and sleeves.
More Options From Stock. Available in two surface finishes; TG&P and Fine Turned Oversize (The size will make the size), and rough machined heavy wall bushing stock. Tight tolerance TG&P will often accept bearings with no further machining. Limited Options. Commercially available as Cold Drawn. Center-less Ground, or peeled. Tolerances are plus and minus. Most often requires machining the next largest size for bearings fit. Difficult machining causes bow and twist, etc.
Long Lengths. On the shelf in lengths to 29ft. Sold also as cut lengths, even to 17 and 18ft dead lengths. No splicing or welding is required. Offered as random lengths covering a broad length range. Also supplied cut to your exact lengths. Short pieces, or long cut bars are no problem. Standard Commercial Lengths are 10 to 13ft random. Difficult to purchase as small cut lengths. Difficult to purchase as long cut lengths.

NASS 45® vs. 400 Series Commercial Grade Stainless

Nass 45 PSQ Stainless Steel 410 & 416 Stainless Steel
High Degree Of Corrosion Resistance. Like type 316Hardened "PH" Custom Stainless Alloy. Relatively low degree of corrosion resistance compared to 316. General tool room grades of har- denable stainless. Worst of both worlds - not a great stainless. Not a great alloy.
Elevated Strength Levels. Hardness as delivered - 26 to 33RC. Typical Tensile approx. 140K @ 28RC. Can be hardened to 36 to 44RC with very little loss in corrosion resistance. Most often delivered at 22 to 28 RC. Typical Tensile @ 26RC, 120KSI. Additional hardening diminishes corrosion resistance and lowers toughness.
Anti-Galling. Compatible with most stainless, carbon and alloy grades of steel Susceptible To Galling. Parts can seize and tear during routine disassembly.
Easy To Machine without the addition of detrimental additives, such as sulfur and selenium. S, or Se added to 410 to make it easier to machine (416). That inhibits welding, and lowers strength.
Low Carbon Levels (.05) High Carbon Levels (.15), lowers corrosion resistance and toughness. Contributes to corrosion cracking.
Low Degree Of Memory. Low degree of retained stress. Very little movement during machining or in service. High "Memory". retained stress causes bow and twist in thermal treatment, machining, and in service.
High Degree Of Wear Resistance as delivered. Can be safely hardened to wear plate levels of 352 to 425BHN. Very Low Degree Of Wear Resistance. Further hardening diminishes corrosion resistance.
Welds Easily. Welding data is available. In 410, higher carbon increases susceptibility for weld cracks. (416 not recommended for welding).
Elevated Nickel content, with additions of Mo- ly, Columbium and Tantalum for corrosion resistance, strength and toughness. Low Chemistry general tool room grade. No Nickel. Low strength and toughness.
28RC - Charpy V notch impact of near 120ft/lbs @ 70F. %RA=70, %EL=28 28RC - Charpy V notch impact of 38ft/lbs, 70F. %RA=60. %EL=19
Stress corrosion test .1% NaCl+.5% Acetic Acid + H/2S @33RC, 60KSI applied stress. No findings after 500hrs. At 35RC, 60KSI applied stress - visible change after 3 hours.


Associated Steel Corporation is the sole licensed agent for all tradename products that were formerly sold by North American Steel Company. For all inquiries and order placements, please contact Associated Steel Corp.

Phone: 1.800.321.9300
Email: mail@associatedsteel.com
Web: www.associatedsteel.com

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