HAYNES® 230® & HR-120® alloys for Light Weight Vacuum Furnace Heat Treat Baskets Tech Brief

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HAYNES® Alloys for Lightweight Vacuum Heat Treat Furnace Baskets and Fixtures

Every time you run your vacuum furnace, it has to heat and cool whatever you put in it. When you use HAYNES® high-temperature alloys for all of your baskets and fixturing, what you don’t put in the furnace is unnecessary weight. HAYNES HR-120® and 230® alloys not only provide superior performance compared to traditional heat treating fixture materials, they do it with thinner section thickness construction. This allows you to save three ways: (1) reduced heating and cooling cycle times, (2) reduced part rejection from poor quench rate, and (3) increased furnace load capability without increased cycle time or reduced quench rate. Compare the sizes of these alloys required for field-proven equivalent or superior performance relative to traditional materials:

Comparative Stress Rupture Strengths

Resistance to sagging or distortion of vacuum furnace baskets and fixtures at elevated temperatures is directly related to the creep or stress rupture strength of the material of construction. Both 230® and HR-120® alloys exhibit large strength advantages over traditional alloys. This allows for either higher loading capability, or significant reduction in the basket or fixture section thickness.

Nominal Composition

HR-120® Alloy

Nickel 37
Cobalt 3 max.
Iron Balance
Chromium 25
Tungsten 2.5 max.
Molybdenum 2.5 max.
Manganese 0.7
Silicon 0.6
Aluminum 0.1
Carbon 0.05
Boron 0.004
Niobium 0.7
Nitrogen 0.20

*Also known as Columbium

230® Alloy

Nickel Balance
Cobalt 5 max.
Iron 3 max.
Chromium 22
Tungsten 14
Molybdenum 2
Manganese 0.5
Silicon 0.4
Aluminum 0.3
Carbon 0.10
Boron 0.015 max.
Lanthanum 0.02

Field Experience: 230® Alloy vs. Alloy 601

Two baskets were constructed to a 33-inch x 46.5 inch (840mm x 1180 mm x 200 mm) design. One basket was fabricated using 230® alloy plate and round bar with section thicknesses ranging from 1/4-inch to 7/16-inch (6.3 mm to 11.1 mm). The alloy 601 basket was built with section thicknesses ranging from 1/2-inch to 5/8-inch (12.7 mm to 15.9 mm). As fabricated, the alloy 601 basket weighed 111 pounds (50.5 Kg), while the basket made from 230® alloy weighed 63 pounds (28.6 Kg), a 43% weight reduction.

Both baskets were placed in vacuum furnace service to assess the differences in resisting distortion, and to determine the effects of the 230 alloy lightweight construction upon furnace cycle time and quench rate. The condition of the baskets after 250 furnace exposures between 1600 and 1900ºF (870 and 925ºC) is shown in the photograph below.

Even after this relatively short use time, the superior distortion resistance of the 230® alloy basket was evident. The effect of the lightweight construction of the 230® alloy basket was also quite evident in both cycle time and quench rate measurements under various load conditions. Quench cycles consisted of forced nitrogen cooling to 400ºF (205ºC) and then open furnace air cooling to ambient. Results show an average improvement of about 20% in quench time and about 18% quench rate.

Furnace Load Quench Time (min) Quench Time Improvement Quench Rate (min) Quench Rate Improvement*
Trial lbs kg 230® 601 % 230® 601 %
– – – – °F °C °F °C –
1 1140 518 12 16 25 100 56 90 50 11
2 120 55 8 10 20 193 107 154 86 25
3 875 398 13 16 19 112 62 96 53 17
4 156 71 11 13 15 136 76 115 64 18

Comparative Yield Strengths

While stress rupture strength is a key design criteria for building baskets, grids, and fixtures that are resistant to sagging, high-temperature yield strength is important for these components to resist distortion from thermal stresses that arise during heating and cooling. HAYNES® 230® and HR-120® alloys possess significant high-temperature yield strength advantages over traditional alloys, without sacrificing important tensile ductility.

230®

Typical Tensile Properties, Plate

Test Temperature 0.2% Yield Strength Ultimate Tensile Strength Elongation
°F °C ksi MPa ksi MPa %
RT RT 57 395 125 860 50
1000 540 40 275 103 705 53
1200 650 40 275 98 675 55
1400 760 42 275 88 605 53
1600 870 37 255 63 435 65
1800 980 21 145 35 240 83
2000 1095 11 76 20 140 83
2100 1150 7 47 13 91 106
2200 1205 4 30 9 65 109

Typical Rupture Properties, Plate

Test Temperature Approximate Stress Required to Produce Rupture in Hours Shown
1,000 h 10,000 h
°F °C ksi MPa ksi MPa
1200 650 42.5 295 29.0 200
1400 760 20.0 140 14.2 98
1600 870 9.5 66 6.2 43
1800 980 3.0 21 1.6 11
1900 1040 1.8 12 – –
2000 1095 1.0 7 – –
2100 1150 0.6 4 – –

HR-120®

Typical Tensile Properties, Plate

Test Temperature 0.2% Yield Strength Ultimate Tensile Strength Elongation
°F °C ksi MPa ksi MPa %
RT RT 46 375 107 735 50
1000 540 26 175 80 555 61
1200 650 25 170 73 505 60
1400 760 25 175 64 440 50
1600 870 27 185 48 325 51
1800 980 19 135 28 190 81
2000 1095 9 63 15 105 89
2100 1150 – – – – –
2200 1205 4 27 5 34 89

Typical Rupture Properties, Plate

Test Temperature Approximate Stress Required to Produce Rupture in Hours Shown
1,000 h 10,000 h
°F °C ksi MPa ksi MPa
1200 650 – – – –
1400 760 12.0 83 17.0 115
1600 870 5.6 39 8.0 55
1800 980 1.9 13 3.5 24
1900 1040 0.8 6 1.7 12
2000 1095 – – 0.8 6
2100 1150 – – – –