Temperature iron-nickel-based alloys

The cubic BN crystals may also be bonded into strong bodies that make excellent cutting tools for hard iron and nickel-based alloys. Such tools produce red-hot chips and permit the wider use of tough, high temperature alloys which would otherwise be prohibitively difficult to shape (12,20,21) (see... 

Some practical cases are determination of residual stress in steel springs, the effect of mechanical loading on stress relaxation of machined and shot-peened nickel-base alloys,65 determination of residual stress level in turbine engine disks as they accumulate engine cycles,65 66 effect of manufacturing processes on residual stress, measurement of stress gradients in mechanical, electronic and structural components, effect of heat treatment on residual stress in steel coil springs, effect of variable heat treatment temperature on residual stress in iron alloys, measurement of stress in multiphase materials and composites and stress measurements at locations of stress concentrations. 

The Materials Technology Institute of the Chemical Process Industry (MTI) has identified five corrosion tests for iron- and nickel-based alloys, out of which two concern the resistance to crevice corrosion. The method MTI-2, originating from ASTM G48, involves the use of 6% ferric chloride solution for determining the relative resistance of alloys to crevice corrosion in oxidizing chloride environment. The method MTI-4 uses an increase in neutral bulk Cl- concentration at eight levels, ranging from 0.1 to 3% NaCl, to establish the minimum critical Cl concentration that produces crevice corrosion at room temperature (20-24°C).43,44... 

The compositions of the alloys evaluated in Phase I are summarized in Table III. These alloys represent most classes of high-temperature iron-, nickel-, and cobalt-base alloys that could be considered for coal gasification service. Pack aluminized and chromized coatings on AISI 310 and IN-800 were also evaluated in the test program. 

As a result of the formation of a protective layer of iron fluorides, carbon steel is resistant to HF as long as its water content does not exceed 3% and the temperature 70 °C. Most equipment is built of this material. However, if the velocity of the fluids at the surface of the metal is more than 1 m/s, the protective layer can be removed by erosion. Thus, when process conditions are too aggressive, the use of nickel-based alloys becomes essential Alloy... 

The development of heat-resistant alloys was similarly lengthy and inefficient. In the 1970s the protective oxide layers on nickel-based alloys were much improved by alloying them with elements that resulted in a more stable and tenacious layers of alumina versus chromia. It is only now that the concept of alumina protective layers is being applied to more cost-effective and high-temperature iron-based heat-resistant alloys, effectively producing a new class of stainless steels based on the principles of selective oxidation and advanced microstructural control of precipitates for strengthening. ... 

This practice covers procedures for the identification and measurement of the extent of carburization in a metal sample and for the interpretation and evaluation of the effects of carburization. It applies mainly to iron- and nickel-based alloys for high temperature appUcations. 

Cobalt is a metal with magnetic properties similar to those of iron. Its salts give glass a beautiful deep-blue colon Cobalt-based alloys have long been used in the manufacturing industry. An addition of 20% cobalt to chromium-nickel-based alloys, used for turbine blades and burner lines in aircraft engines, improves the high-temperature properties. Cobalt powder is an important component in cemented carbides (hard metals). Cobalt is also an essential element for life and important for humans and animals. It is present mainly in the form of vitamin Bjj. The artificially produced isotope Co is used as a source of intense g-radiation. It is used in industry and in radioisotope therapy. 

The nickel-based alloys are sometimes referred as superalloys. They have been defined as those possessing good high-temperature strength and oxidation resistance and are alloys of nickel, cobalt, and iron that contain... 

Alloy 600, also known as Inconel, is a nickel-based alloy with about 16% chromium and 7% iron that is used primarily to resist corrosive atmospheres at elevated temperatures. The chemical composition will be found in Table 15.16. 

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