Saturated steamapplication

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Saturated steam table

Saturated steam table

Saturated steam has a fixed pressure & temperature related table.

• 3 barG saturated steam temperature is 143.6° C

• 5 barG saturated steam temperature is 158.8° C

• 10 barG saturated steam temperature is 184.1° C

• 15 barG saturated steam temperature is 201.4° C

• 20 barG saturated steam temperature is 214.9 ° C

Metal seated valve

Bronze gate valve

Malleable iron/Ductile

iron gate valve

Forged steel gate

valve

Cast steel gate valve

Bronze globe valve

Malleable iron/Ductile iron globe

valve

Forged steel globe

valve

Cast steel globe valve

Bronze check valve

Malleable iron/Ductile iron check

valve

Forged steel check

valve

Cast steel check valve

Metal seated valve

High performance or eccentric butterfly valve can be used for saturated steam application

Metal seated ball valve can be used for saturated steam

application

Bronze valve for saturated steam

Cast iron valve for saturated steam

Cast iron family

Gray iron, or grey cast iron, is a type of cast iron that has a graphitic microstructure. It is named after the gray colour of the fracture it forms, which is due to the presence of graphite. Since the carbon content is high, it becomes brittle if given tension.

Malleable iron is cast as white iron, the structure being a metastable carbide in a pearlitic matrix. Through an annealing heat treatment, the brittle structure as first cast is transformed into the malleable form. Carbon agglomerates into small roughly spherical aggregates of graphite leaving a matrix of ferrite or pearlite according to the exact heat treatment used.

Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and SG iron, is a type of graphite-rich cast iron . While most varieties of cast iron are weak in tension brittle, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions.

Cast iron vs Malleable iron vs Ductile iron

As for the casting process, the production for malleable iron & ductile iron are made similar with the normal casting iron• Ductile iron has a inoculation process. Inoculation means we will add the spheroidizing

agents during melting and pouring process to make the graphite into ball shape. • The production of malleable iron includes a special heat treatment process, which can

make the graphite into cottony shape.• Malleable iron & ductile iron are generally superior to grey irons, regarding their yield

strength. The max yield strength of ductile iron is 40k psi (grey iron is not very malleable or strong it fractures/breaks easily)

• Malleable iron & ductile iron are more flexible and elastic than other cast irons. It has higher strengths, greater elongation and better resistance to impact than grey iron (so it is better than grey iron in handling temperature expansion problem such as in steam application)

• The malleable iron & ductile iron family offers the design engineer a unique combination of strength, wear and fatigue resistance and toughness as well as excellent ductility characteristics

Carbon content in iron & steel

Malleable iron/Ductile iron valve for saturated steam

Forged steel valve for saturated steam

Class 800 forged steel valve with standard A-105 type of material can stand saturated steam without problem !

For example: • 20 barG of saturated steam

temperature is 214.9°C • At 204.5°C class 800 forged steel

valve can stand 116.6 bar pressure

Cast steel valve for saturated steam

Class 150 or class 300 cast steel valve with standard A216-WCB type of material can stand saturated steam without problem !

For example: • 20 barG (290 psiG) of

saturated steam temperature is 214.9°C (417°F)

• At 400°F (204°C) class 300 cast steel valve can stand 635 psi (43.8 bar) pressure

Valve’s seat material for saturated steam

Valve’s seat ring

Steam is very abrasive !To prevent wear of the internal part of the metal seated valve

the valve’s seat ring have to be stellited

Valve’s seat material for saturated steam

If the valve’s seat ring is stellited The trim material no 8 is choosen !

Soft seated valve

Ball valve has soft seat can be used for saturated steam

application But the pressure-temperature rating is based on the

soft seat material

Concentric butterfly valve cannot be used for saturated steam

application

Ball valve seat pressure temperature rating

PTFE seat material (T)At 10 bar pressure it can stand 210°C temperature10 bar saturated steam temperature is only 184.1°C

Even though 18 bar saturated steam temperature is 210°C PTFE seat of a ball valve can stand 10 bar saturated steam only !

Ball valve seat pressure temperature rating

PTFE seat material (blue line)At 10 bar pressure it can stand 210°C temperature

PTFE seat of a ball valve can stand 10 bar saturated steam only ANSI class 150 ball valve is suitable for this job !

Superheated steamapplication

Saturated steam

Superheat tubes

Superheat steam

Superheated steam is created by further heating wet or saturated steam beyond

the saturated steam point in a water tube steam boiler.

This yields steam that has a higher temperature and lower density than

saturated steam at the same pressure. Superheated steam is mainly used in propulsion/drive applications such as

turbines, and not so much is used for heat transfer applications.

Superheat steam

Superheat steam does not have a fixed

pressure-temperature relationship like

saturated steam !

Forged steel valve for superheated steam

For example:Application: Superheated steam, 500°C & 40 bar

If we look at the A-105 forged steel material P/T-chartAt 510°C temperature the class 1500 valve can stand 35.5

bar pressure only

Forged steel valve for superheated steam

For example:Application: Superheated steam, 500°C & 40 bar

If we look at the A182-F22 forged steel material P/T-chartAt 510°C temperature the class 1500 valve can stand 130

bar pressure !

Cast steel valve for superheated steam

For example:Application: Superheated steam, 400°C (753°F) & 40 bar (580 psi)

If we look at the A216-WCB cast steel material P/T chartAt 750°F temperature the class 300 valve can stand 505 psi pressure only

Cast steel valve for superheated steam

For example:Application: Superheated steam, 400°C (753°F) & 40 bar (580 psi)

If we look at the A217-WC1 cast steel material P/T chartAt 750°F temperature the class 300 valve can stand 530 psi pressure only

Cast steel valve for superheated steam

For example:Application: Superheated steam, 400°C (753°F) & 40 bar (580 psi)

If we look at the A216-WCB cast steel material P/T chartAt 750°F temperature the class 600 valve can stand 1,010 psi pressure

Valve’s seat material for superheated steam

Superheat steam is very abrasiveIf the valve’s seat ring + the valve’s disc are stellited

The trim material no 5 is choosen !