Search Results for 304H

This appendix provides property data, including strength, tensile properties, elastic constants, and hardness, for 300-series powder metal stainless steels.

This chapter discusses material-related problems associated with coal-fired burners. It explains how high temperatures affect heat-absorbing surfaces in furnace combustion areas and in the convection pass of superheaters and reheaters. It describes how low-NOx combustion technology, intended to reduce NOx emissions, accelerates tube wall wastage. It also covers circumferential cracking in furnace waterwalls, thermal fatigue cracking induced by waterlances and water cannons, superheater-reheater corrosion, and erosion in fluidized-bed boilers.

Boilers are often classified based on the maximum operating temperature and pressure for which they are designed. Classifications, in ascending order, are subcritical, supercritical, ultra-supercritical, and to advanced ultra-supercritical. At each higher operating point comes greater efficiency, as well as greater demand on construction materials. This chapter discusses the primary requirements for boiler tube materials, including oxidation and corrosion resistance, fatigue strength, thermal conductivity, and the ability to resist creep and rupture. It also provides information on various steels and alloys, covering cost, engineering specifications, and ease of use.

This chapter discusses two damage mechanisms in which stress plays a major role. In the one case, stress causes cracks in the oxide scale on metals, leading to preferential corrosion attack. An example from industry of this type of failure is the circumferential cracking that occurs on the waterwall tubes of supercritical coal-fired boilers fired under low NOx combustion conditions, conducive to the production of sulfidizing environments. In the other case, stress contributes to brittle fracture in the form of intergranular cracking. The phenomenon, which is known by various names, typically occurs at the lower end of the intermediate temperature range and has been observed in ferritic steels, stainless steels, Fe-Ni-Cr alloys, and nickel-base alloys, as described in the chapter.

This appendix contains tables listing the composition of austenitic, ferrite, martensitic, precipitation-hardenable, and duplex stainless steels and of Alloy Casting Institute heat- and corrosion-resisting casting alloys.

This chapter presents the early classes of stainless steel. These include martensitic alloys, austenitic alloys, and ferritic alloys. It also presents stainless steel trade names. The chapter describes standardized designation for type 304 stainless steel by various specification organizations.