03 - Weld Flange with Rod - ASME IX

This welding process qualification of welder and welding process is necessary , documents drawn from certification of welded samples and welding processes , which has the backing of a qualified engineer to perform this task .

For each specific material dissimilar material and a mounting flange and the stem is required and welding procedure qualification of welding , so that a single procedure and qualification is not valid for all types steels .

Types of Welding



Materials commonly used

Material	T máxima	Comments
Carbon Black Iron or Steel	540 °C	Satisfactory in non-corrosive atmospheres
Ductile Iron Pearlitic	700 °C	Typically used in non-ferrous smelter
304 stainless steel	850 °C	Good corrosion resistance , can be used in oxidizing atmosphere , reducing , neutral and vacuum. the use in the presence of sulfur or reducing flame is not recommended.
316 stainless steel	850 °C	Higher corrosion resistance than 304 stainless steel . Good resistance to acids and alkalis.
Stainless steel 310	1100 °C	Good oxidation resistance properties at high temperatures. Usable in oxidizing atmosphere , reducing , neutral, or in vacuo. Good for use in sulphurous atmosphere.
Chrome steel 446	1100 °C	Excellent resistance to oxidation and corrosion and high temperatures , good resistance to sulfur atmospheres.
Inconel 600	1150 °C	Excellent resistance to oxidation at high temperatures. Its use in atmospheres containing sulfur above 500 ° C should be avoided.

Failure of a protection well

Process Speed

• The speed and direction of the process fluid determined by the ratio of space time by (m / s ft / s, etc.)


Oscillation

• Vibration - (mechanical Oscillation) is caused by repeated variation of the forces that act in the process. These forces generate an impulse causing it to have a motion similar to a pendulum.

• Resonance - When a protection well vibrates, it creates and stores its own energy, it vibrates using its own frequency. If the vibration frequency corresponds to the resonant frequency of the shaft protection, you can vibrate to the point of rupture.


Pressure

• The protection of well should be specified according to the pressure exerted on it in the process.

• The wall thickness should be adequate.


Compatibility with the process


• Erosion and corrosion should be considered when choosing the thermowell material.


overtemperature

• Use at higher temperatures than recommended, will affect the well resistance.