Allowable Stress in ASME VIII, B31.3, API 650, API 653

Basis of Allowable (Design) Stress in ASME VIII Pressure Vessel and ASME I Boiler;  (The Allowable Stress from SMTS and Allowable Stress) as well as the ASME B31.3 Proces Piping, for ASME VIII Pressure Vessel and ASME I Boiler values Allowable Tensile Stress of Material , the Code permits used to calculate the thickness and composition. The variables that are used to handle the pressure of the Pressure Vessel and Boiler will be specified in the ASME BPVC Section II Part D, which is generally equal to A value that is less than 1/3.5 Tensile Strength and 2/3 Yield Strength … Continue reading Allowable Stress in ASME VIII, B31.3, API 650, API 653

Tension Test Acceptance Criteria for Welding Procedure Qualification

Tension Test Acceptance Criteria for Welding Procedure Qualification per ASME IX;  To qualify the welding procedure according to the ASME Section IX, the mechanical properties of the test coupon must be tested. Tension Test, which is the test of the strength of the weld by The principle of ASME is that Weld Metal must be stronger than or equal to the strength of Base Metal. Therefore, the result of the Tension Test will have Acceptance Criteria as follows. The workpiece is torn/break at Base Metal: Ultimate Tensile Strength (UTS) or Failure Stress of the workpiece must be greater than 95% … Continue reading Tension Test Acceptance Criteria for Welding Procedure Qualification

What is Lamellar tearing

Welding Defects – Lamellar Tearing;  Lamellar Tear is a crack that is a step in the base metal under the welding line. The cracks lie parallel to the work surface, especially with the Rolled Steel Plate. Lamellar Tear is caused by Tensile Stress in Through-Thickness direction. This comes from the shrinkage of the weld and the base metal itself has impurities or inclusions that are parallel to the work surface Thus causing a tear or crack Lamellar Tearing up. Continue reading What is Lamellar tearing

What is Caustic corrosion cracking

External Evidence of Caustic Leaking; Carbon Steel Piping used for Caustic Service (NaOH content) may be damaged by Caustic Cracking, especially in areas with welded and discrete areas that have high stress. Caustic leaks or leaks from the cracks will look like White salt, which can be seen with the naked eye. Therefore, when doing an external visual inspection for Caustic Piping, don’t forget to look for “White Salt” which is an Evidence that indicates that our Caustic pipe is leaking. External Evidence of Caustic Leaking – Caustic Cracking on Socket Welded Piping;  Example of Caustic leakage from Caustic (NaOH) Injection Piping … Continue reading What is Caustic corrosion cracking

Circumferential vs Longitudinal Stress

Circumferential vs Longitudinal Stress of a Cylindrical Shell in ASME VIII Vessels;  Let’s look at the formula for calculating the Cylindrical Shell thickness of the ASME Section VIII Pressure Vessel. We can see that the Minimum Thickness calculated from Circumferential Stress is approximate twice the thickness calculated from Longitudinal Stress. This is because the Circumferential Stress is twice as much as Longitudinal Stress. Therefore, when calculating Shell thickness, use the formula of Circumferential Stress. Refer to: What is Hoop Stress in pressure vessel? Continue reading Circumferential vs Longitudinal Stress

What is Soil Corrosion

Soil to Air Interface – Zone of Corrosion on API 570 Piping; The area where the pipelines fall underground, or soil-to-air interface, is the area that has a high chance of external corrosion if Wrapping or Coating is damaged. Due to the difference in temperature, humidity and oxygen in the area, the API 570 stipulates that 6 inches above and 12 inches below the soil surface is the Soil-to-air Interface zone that should be Reviewed. Inspection of Soil-to-air Interface for Underground Piping;  For example, to monitor underground pipes ( Underground, Piping) in a pipe underground or Soil-to-air Interface by digging tube down … Continue reading What is Soil Corrosion

Steam trap design in piping system

Why does a Steam Heat Exchanger or any Steam Heater have a Steam Trap: 1st reason: On Outlet line, Steam-out of the Heat Exchanger may also heat or condensated at Steam outlet, therefore, a Steam Trap at Outlet line of Heat Exchanger for trap the Steam to condense into water  before forwarding it to condensate main line (Saving Steam). 2nd reason: The Steam on the Heat Exchanger may be Water Condensate contaminated, so they have to set Steam Trap with Steam Inlet line to prevent damage from Two-phase flow steam erosion occurred in Heat Exchanger. (Corrosion/Errosion Protection) Example of Steam … Continue reading Steam trap design in piping system

Flash point, Boiling Point, and Autoignition point.

Flash Point VS. Autoignition Temperature;  Flash Point is the lowest temperature at which a material or substance ( Flammable materiales) vapors ( Vapor was) enough to be flammable when mixed with air (Air) and a power source ( With The the Source, Ignition). Autoignition Temperature is the temperature at which the vapor of materials or substances ( Flammable materiales) can spontaneously ignite when mixed with air (Air) without a power source ( online Without the Source, Ignition). For example, Gasoline can ignite from a temperature of 43 degrees Celsius (Flash Point). If sparks occur And can ignite spontaneously at temperatures from 280 degrees Celsius ( … Continue reading Flash point, Boiling Point, and Autoignition point.

Vessel rubber lining inspection

Vessel and Tank Inspection – Rubber Lining Inspection;  Within the Piping, Vessel or Tank, some will be done with Lining or Coating to Prevent Corrosion and Erosion. During inspection (in-service), damages that will occur to the Lining, such as separation, breakage, swelling. If we find that Lining damage. We have to dismantle the lining to check for damage to the metal surface of the Vessel beneath the lining (in the picture is an example of the Rubber Lining inside the tank that is very cracked and swollen, and the Corrosion that occurs on the metal surface of the tank under the Rubber Lining) Continue reading Vessel rubber lining inspection