Corrosion Resistant UNS N05500 Special Alloys For Clean Energy And Oceaneering

Corrosion resistant alloy UNS N05500, Monel K-500, W.Nr.2.4375 shaft, rod and drill collar for oceaneering

PRODUCT

Corrosion resistant alloy UNS N05500, alloy K-500, Monel® K-500, W.Nr.2.4375 shaft, rod, bar and pipe etc for oil well drill collars and instruments, pump shafts and impellers, non-magnetic housings, ety lifts and valves for oil and gas production, oil-well surveying equipment, shafts of centrifugal pumps in marine service, corrosion-resistant springs and bolts etc.

EQUIVALENT DESIGNATION

Alloy K-500, Monel® K-500, W.Nr.2.4375

PRODUCT FORM

Alloy UNS N05500 is available in the form of pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.

OVERVIEW

UNS N05500 (Monel® K-500) is a nickel-copper alloy which combines the excellent corrosion resistance of UNS N04400 (Monel® 400) with the added advantages of greater strength and hardness. The increased properties are obtained by adding aluminum and titanium to the nickel-copper base, and by heating under controlled conditions so that submicroscopic particles of Ni3 (Ti, Al) are precipitated throughout the matrix. The thermal processing used to effect precipitation is commonly called age hardening or aging.

APPLICATION

Typical applications for UNS N05500 products are chains and cables, fasteners and springs for marine service; pump and valve components for chemical processing; doctor blades and scrapers for pulp processing in paper production; oil well drill collars and instruments, pump shafts and impellers, non-magnetic housings, ety lifts and valves for oil and gas production; and sensors and other electronic components.

UNS N05500 is approved by the ASME Boiler and Pressure Vessel Code as an acceptable material for use as bolting.

Since its combination of low magnetic permeability, high strength and good corrosion resistance, UNS N05500 has been used to advantage in a number of applications, notably oil-well surveying equipment and electronic components.

UNS N05500 has been found to have exceptionally good dimensional stability, both in long-time exposure tests and in cyclic tests. This property of the alloy has led to its use in high-precision devices, such as gyros.

The combination of very low corrosion rates in high-velocity sea water and high strength make alloy UNS N05500 particularly suitable for shafts of centrifugal pumps in marine service.

UNS N05500 is useful for corrosion-resistant springs at temperature up to 500°F.

CHEMICAL COMPOSITION (wt%):

PHYSICAL PROPERTY

Density: 8.44g/cm³

Melting range: 1315-1350℃

CORROSION RESISTANCE

The corrosion resistance of UNS N05500 is substantially equivalent to that of alloy UNS N04400 except that, when in the age-hardened condition, alloy UNS N05500 has a greater tendency toward stress-corrosion cracking in some environments.

UNS N05500 has been found to be resistant to a sour-gas environment. After 6 days of continuous immersion in saturated (3500 ppm) hydrogen sulfide solutions at acidic and basic pHs (ranging from 1.0 to 11.0), U-bend specimens of age-hardened sheet showed no cracking. Hardness of the specimens ranged from 28 to 40 Rc.

The combination of very low corrosion rates in high-velocity sea water and high strength make alloy UNS N05500 particularly suitable for shafts of centrifugal pumps in marine service. In stagnant or slow-moving sea water, fouling may occur followed by pitting, but this pitting slows down after a fairly rapid initial attack.

MECHANICAL PROPERTIES

Nominal mechanical property ranges^a

a The ranges shown are composites for various product sizes and therefore are not suitable for specification purposes.

b Nominal properties for material age-hardened to produce maximum properties

c Properties shown are for sizes 0.0625 - 0.250-in. diameter. Properties for other sizes may vary from these.

HEAT TREATMENT

Solution annealing

UNS N05500 is hardened by the formation of submicroscopic particles of a secondary phase, Ni₃(Ti,Al). Formation of the particles takes place as a solid state reaction during an age-hardening (or precipitation-hardening) heat treatment. Prior to the aging treatment, the alloy component should be solution-annealed to dissolve any phases that may have formed in the alloy during previous processing. Solution annealing is normally performed by heating hot-finished products to 1800°F and cold-worked products to 1900°F.

Process annealing

During mechanical processing in production and subsequent forming of alloy UNS N05500 products, intermediate process annealing may be required to soften the product. Such anneals recrystallize the structure and are typically conducted at temperatures between 1400°-1600 °F.

Age hardening

The following age-hardening procedures are recommended for achievement of maximum properties.

(1) Soft material (140-180 Brinell, 75-90 Rockwell B).

Hold for 16 hr at 1100° to 1125°F followed by furnace cooling at a rate of 15° to 25°F per hr to 900°F. Cooling from 900°F to room temperature may be carried out by furnace or air cooling, or by quenching, without regard for cooling rate.

(2) Moderately cold-worked material (175-250 Brinell, 8-25 Rockwell C).

Hold for 8 hr or longer at 1100° to 1125°F, followed by cooling to 900°F at a rate not to exceed 15° to 25°F per hr. Higher hardnesses can be obtained by holding for as long as 16 hr at temperature, particularly if the material has been cold-worked only slightly. As a general rule, material with an initial hardness of 175-200 Brinell should be held the full 16 hr. Material close to the top figure of 250 Brinell (25 Rockwell C) should attain full hardness in 8 hr.

(3) Fully cold-worked material (260-325 Brinell, 25-35 Rockwell C).

Hold for 6 hr or longer at 980° to 1000°F followed by cooling to 900°F at a rate not exceeding 15° to 25°F per hr. In some instances slightly higher hardnesses may be obtained (particularly with material near the lower end of the hardness range) by holding 8 to 10 hr at temperature.

FABRICATING

UNS N05500 is readily fabricated by standard commercial procedures.

Hot forming

Proper temperature during deformation is the most important factor in achievement of hot malleability. Maximum recommended heating temperature for hot-working UNS N05500 is 2100°F. Metal should be charged into a hot furnace and withdrawn when uniformly heated. The hot-working temperature range is 1600 to 2100°F. Heavy work is best done between 1900 and 2100°F; working below 1600°F is not recommended.

Cold forming

In the annealed condition, alloy UNS N05500 can be cold worked by standard procedures. Although the alloy requires considerable power to form, it has excellent ductility. Its increase in hardness with .increasing cold work.

Machining

Heavy machining of alloy UNS N05500 is best accomplished when the material is in the annealed condition or hot worked and quenched condition. Age-hardened material, however, can be finish machined to close tolerances and fine finishes. The recommended practice, therefore, is to machine slightly oversize, age-harden, then finish to size. During aging, a slight permanent contraction (about 0.0002 in./in.) takes place, but little warpage occurs because of the low temperatures and slow cooling rates involved.

Joining

UNS N05500 products may be joined by conventional processes and procedures.

Welding alloy UNS N05500 is best accomplished by the gas-tungsten-arc welding (GTAW) process. MONEL filler metal 60 is normally used. However, the weldments are not age hardenable and, thus, do not have strength matching that of the hardened base metal. Weldments requiring strength similar to the aged base metal should be deposited with filler metal of matching composition.

STANDARD SPECIFICATION

UNS N05500 is listed in NACE MR 0175 for oil and gas service. This alloy is furnished in a wide range of standard mill forms including pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.

BS3072 NA18 Sheet and Plate

BS3073 NA18 Strip

QQ-N-286 Plate, Sheet and Strip

DIN 17750 Plate, Sheet and Strip

ISO 6208 Plate, Sheet and Strip

BS3075 NA18 Wire

BS3076 NA18 Rod and Bar

ASTM B865 Rod and Bar

DIN 17752 Rod and Bar

DIN 17753 Wire

DIN 17754 Forgings

QQ-N-286 Rod, Bar, Wire, and Forgings

SAE AMS 4676 Rod and Bar

ASME Code Case 1192 Rod and Bar

ISO 9723 Bar

ISO 9724 Wire

ISO 9725 Forgings

BS 3074 NA18 Seamless Pipe and Tube

DIN 17751 Pipe and Tube

DIN 17743 Chemical Composition

SAE AMS 4676 Chemical Composition

QQ-N-286 Chemical Composition

COMPETITIVE ADVANTAGE:

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Hundreds of patent technologies.

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