Steel Pipe Fittings

Commercial applications involve furnace components and fixtures requiring strength and oxidation resistance at temperatures up to 2000 degrees F.

Both materials remain available, subject to commercial considerations, and certain specifications which restrict the service temperature of some grades of INCOLOY alloy 800H.

Incoloy Alloy 800HT applications have extended from petrochemical processing reformer tubing, to bellows and flare tips in refinery service.

In power generation, superheater and reheater tubing has also employed the material 800HT.

Incoloy 800HT, also known as ¡°Alloy 800HT¡±, is designated as UNS N08811 or DIN W.Nr. 1.4959. It is an iron-nickel-chromium alloy having the same basic composition as Incoloy 800 and Incoloy 800H but with significantly higher creep-rupture strength.

The higher strength results from deliberate control of the carbon, aluminum, and titanium contents in conjunction with a high-temperature anneal.

Used in chemical and petroleum processing, in power plants for superheater and reheater tubing, in industrial furnaces, and for heat treating equipment.

Incoloy 800, 800H and 800HT have nearly identical chemical composition and physical properties.

The major differences between these alloys are their mechanical properties which stem from the restricted compositions of alloys 800H and 800HT and the high-temperature anneals used for these alloys.

Alloy 800 has higher mechanical properties at room temperature and during short-time exposure to elevated temperatures, whereas alloys 800H and 800HT have superior creep and rupture strength during extended high-temperature exposure.

Incoloy 800, 800H, and 800HT are nickel-iron-chromium alloys with good strength and excellent resistance to oxidation and carburization in high-temperature exposure.

These nickel steel alloys are identical except for the higher level of carbon in alloy 800H, and the addition of up to 1.20 percent aluminum and titanium in alloy 800HT. Incoloy 800 was the first of these alloys and it was slightly modified into Incoloy 800H.

This modification was to control carbon (.05-.10%) and grain size to optimize stress rupture properties. Incoloy 800HT has further modifications to the combined titanium and aluminum levels (.85-1.20%) to ensure optimum high temperature properties.

Incoloy 800HT is a nickel-iron-chromium alloy, and also a modified version of alloy 800.

The nickel alloy is dual certified (800H/HT) and combines the properties of both forms. Incoloy 800H/HT alloy was intended for high temperature structural applications.

It has high creep-rupture strength. The following datasheet gives an overview of Incoloy 800HT.

The nickel content makes the alloys highly resistant to both chloride stress-corrosion cracking and to embrittlement from precipitation of sigma phase.

Alloy 800HT / Incoloy 800HT is a controlled composition derivative of INCOLOY? alloy 800H (UNS N08810) and is used for the same creep resistant applications, however the combined effects of mechanical and thermal processing of the alloy permit higher design stresses to be incorporated than are permitted for the conventional alloy.

The combined effects of mechanical and thermal processing of Incoloy Alloy 800HT permit higher design stresses to be incorporated than are permitted for the conventional Alloy 800H.

The regular products of A234 WPB pipe fittings are elbows,tees,reducers,caps,cross.There are seamless and ERW A234 WPB pipe fittings,the seamless A234 WPB pipe fittings means the fittings are made from the seamless steel pipes,ERW means the fittings are made from ERW steel pipes.

Welded A234 WPB pipe fittings mean the large sizes fittings which are pieces welded from steel plates.

In these standard Grade WPB is the most common material used for medium and high temperature pipelines. W means weldable, P means pressure, B is grade b, refer to the minimum yield strength.

Grade WPB fittings made from the steel pipes or plates maximum C is 0.35%.

Forging fittings Carbon content 0.35% maximum and Silicon content 0.35% maximum, no minimum.

For the seamless steel pipe fittings refers to the fittings raw material from the seamless steel pipes and tubes. Thus the welded steel pipe fittings covers the fittings raw material from welded steel pipes.

ASTM A234 specification does not cover cast welding fittings or fittings machined from castings.

The manufacturing processes for pipe fittings includes forging and shaping operations. As well as pressing, hammering, piercing, extruding, upsetting, rolling, bending, fusion welding and machining. Or the processes of combination of two or more of these operations.

ASTM A234 standard steel pipe fittings have been widely applied in pipeline systems, it includes carbon and alloy steel material.

ASTM A234 covers wrought carbon steel and alloy steel fittings of seamless and welded construction covered by the latest revision of ASME B16.9, B16.11, MSS-SP-79, MSS-SP-83, MSS-SP-95, and MSS-SP-97.

Steel pipe fitting are made of carbon or alloy steel pipe, plates, profiles, to a certain shape that could make a function (Change the fluids direction or rate) in pipeline systems. Mostly these fittings includes steel elbow (45 or 90 degree bend), tee, reducer (concentric or eccentric reducer), cross, caps, nipple, flanges, gasket, studs and etc.