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

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.

What is Holiday Test ?

Holiday Test – Overview;  A holiday test here refers to defects in coating or lining, which are Pinhole, Void, Crack, Thin Spot or Contaminant.  Holiday Test is a method for checking these defects by providing electricity through the defects in Coating/lining to Workpiece. If any area has a defect, spark or short circuit will occur. Holiday Test will be divided into two(2) main methods. According to the thickness of Coating/lining by Low Voltage or “Wet Sponge” It applies to Coat thickness less than 500 microns of High Voltage or “Spark” is used to Coating thickness greater than 500 microns. Example of understanding the methods: … Continue reading What is Holiday Test ?

Ferrite content in stainless steel and embrittlement

Summary the important notes on this concept: SS will be 885*F (475*C) embrittlement and, or sigma-phase promotion by Ferrite content. The ferrite contained in Austenite SS is kept around 2-5% for weldability. The Embrittlement by Sigma phase is prevented by keep FN < 10 The Embrittlement by 475*C is prevented by keeping FN <14 Example: Some refinery specs required FN on SS347 <9 to prevent the Embrittlement (475*C Embrittle + Sigma phase embrittle)   There are a number of different types of steels that may be referred to as ‘stainless’; previous articles have considered ferritic and precipitation hardening steels for … Continue reading Ferrite content in stainless steel and embrittlement

Barlow formula – Pipe thickness calculation

Barlow’s Formula;  Barlow’s Formula is the relationship between Internal Pressure and working pipelines. Depending on the size and strength of the material, Barlow’s Formula is the basic formula used to calculate the thickness of the straight pipe and Cylindrical pressure vessel shell in  ASME Code. What is “S” Allowable stress: See SMTS and Allowable Stress Continue reading Barlow formula – Pipe thickness calculation

SMTS and Allowable Stress

Specified Minimum Tensile Strength (SMTS) The ASME Code, Specified Minimum Tensile Strength or SMTS mean stress (Stress), the lowest that can make a material damaged or torn apart by tension ( The Tension), which is made from tensile tests ( Tensile Test,. ), also known as Ultimate Tensile Strength (UTS).  How to test and verified the SMTS of weldment: Tension Test Acceptance Criteria for Welding Procedure Qualification Allowable Stress “S”;  For ASME Code,   pressure vessel or pipe design, the code uses the Tensile stress of each material specified in the calculation. Stress that the code specifies or allows is called Allowable Stress “S”, which … Continue reading SMTS and Allowable Stress


If you are in steel industry, have you ever notice what all those chemical composition listed on a steel materials test report really mean? You may only know different steel grade has many different chemical composition and elements in different amount. Here in this post, we sort out and list 21 chemical elements and effects on steel properties. 21 Chemical Elements and Effects on Steel Mechanical Properties Steel in general is an alloy of carbon and iron, it does contain many other elements, some of which are retained from the steel making process, other elements are added to produce specific properties. … Continue reading ALLOY ELEMENT AFFECTION IN STEEL PROPERTIES