K94800 / Glass Seal 48 Special Alloys For Automotive Nickel Iron Controlled Expansion Alloy

Alloy 48 (K94800, W.Nr. 1.3922, Glass seal 48) bar, tube, strip, wire for automotive and industrial electric lamp bulb

1 PRODUCT

Nickel iron alloy 48 semi-products for automotive and industrial electric lamp bulbs.

Alloy 42 is available in following standard semi-finished forms:

Sheet

Delivery condition: Hot or cold rolled, heat treated, descaled or pickled

Strip

Delivery condition: Cold rolled, heat treated, pickled or bright annealed

Bar and Rod

Delivery condition: Forged, rolled, drawn, heat treated, oxidized, descaled or pickled, turned, peeled, ground or polished

Wire (profile, round, flats, square)

Delivery condition: Drawn bright, ¼ hard to hard, bright annealed in rings, containers, on spools and headstocks

Wire rod

Delivery condition: hot rolled (dia.5.5mm to 40mm)

Others

Other shapes and dimensions such as discs, rings, seamless pipes and forgings can be requested.

2 EQUIVALENT DESIGNATION

UNS K94800, W.Nr. 1.3922, 1.3926, 1.3927, Glass seal 48, Nilo® alloy 48, Invar® 48, Pernifer 48

3 OVERVIEW

Alloy 48 is a binary nickel-iron controlled expansion alloy containing 48% nickel, used in both for its controlled expansion characteristics as well as it’s magnetic shielding capabilities.

4 APPLICATION

Alloy 48 is mainly used for glass-to-metal seals in soft lead or soda lime type glasses, and variety of electronic tubes, automotive and industrial lamps, relay switches, transformers and cathode ray tubes, and specialty hermetic devices. It is also used for thermostats in industrial applications up to 450°C (840°F).

5 CHEMICAL COMPOSITION (wt%):

6 PHYSICAL PROPERTY

Density at 20°C: 8.25 g/cm³ (0.298 lb/in³)

Modulus of elasticity in tension: 23.2 x 10³ ksi (160 x 10³MPa)

Curie temperature: 880°F (471°C)

Specific heat: 0.12 Cal/g- °C (0.12 BTU/lbm- °F)

Table 6-1 Melting and inflection points

Table 6-2 Thermal conductivity at 20°C (68°F)

Table 6-3 Electrical resistivity

Table 6-4 Typical thermal expansion of Alloy 48

7 MECHANICAL PROPERTIES

Table 7-1 Typical mechanical properties of Alloy 48 hot rolled bar in annealed condition

Table 7-2 Hardness

8 WORKING INSTRUCTION

Alloys 48 can be hot or cold worked, machined and formed by processes similar to those used for austenitic stainless steels.

Heat treatment

Although the nickel-iron low expansion alloys are not hardenable, annealing and stress relief thermal treatments are at times necessary to promote structure uniformity and dimensional stability. The relief of stresses introduced by severe forming, bending, or machining, can be accomplished by annealing at temperatures of approximately 1400 to 1800°F (760 to 982°C) for a time sufficient, to thoroughly heat through the section. However, the nickel-irons will oxidize readily at these high temperatures. When annealing cannot be done in a non-oxidizing enviroment (vacuum, dry hydrogen, dissociated ammonia, etc.) sufficient material must be allowed on work pieces to clean-up by light grinding, pickling, etc., after annealing. Stress relief for sections having light finishing cuts or grinding performed after annealing is accomplished by heating to 600 to 800°F (316 to 427°C), for a time to uniformly heat through the work piece.

Forming

All of the nickel-iron controlled expansion alloys can be hot forged, upset, formed, etc., at temperatures between 1800 to 2100°F (982 to 1149°C). However, heating for hot working must be done uniformly at slow rates from relatively cold furnaces (black) to minimize the potential for cracking through large sections as a result of differential thermal expansion stresses. Large forgings should be annealed to promote uniformity after hot working.

Machining

The alloy should be machined in the annealed condition, using high speed steel or tungsten carbide tipped tools. Cutting compounds should be straight cutting oil E.P. medium duty, or soluble oil 20:1 dilution for turning, drilling and milling. Lower dilution ratios should be used for other machining methods.

The following feeds and speeds can be used as a general guide:

9 STANDARD SPECIFICATION

DIN 17745 Plate, sheet, bar, rod

AFNOR NF A54-301 Composition

ASTM F-30 Sheet, strip, rod, bar, tubing and wire

MIL 1-23011 Class 3

AMS 1-23011 Class 3

10 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) Patented technologies.

(4) Ultra-purity smelting process: VIM + IG-ESR + VAR

(5) Excellent high performance.

11 BUSINESS TERM