Piping interview and questions Part-2

Piping interview questions and answers -Part 1

Important stainless steel grades

Stainless Steel

Stainless Steel

Stainless steel is a group of heat and corrosion resistant steels. They have in general higher resistance to corrosion in some definite environment, as well as a higher resistance to scaling at high temperature.

Stainless Steel are iron-based alloys containing a minimum of 10.5% chromium with or without other alloying elements. Based on the alloy content and the micro structure,stainless steels are classified into three major categories viz, Austenitic, Ferritic, and Martensite.

Austenitic

This category of steel contains 16-26% Chromium and 6 to 22% Nickel. They are non magnetic in annealed condition and have excellent corrosion resistance. They are not hardenable by heat treatment.

However, they can develope high strength on cold working. They have excellent weldability, formability, hygiene factor and cryogenic properties. On cold working they exhibit different degrees of magnetism. They are identified in the AISI 300 series.

Ferritic

This category of stainless steel contains 10.5  to 30% Chromium without any Nickel. They are Ferro-magnetic in nature and generally not hardenable by any heat treatment. These steel posses good resistance to stress corrosion cracking and moderate weldability & formability.

They are identified in the AISI 400 series.

Martensitic

This group contains 11 to 14% Chromium without any Nickel but with a higher carbon content
compared to the  Austenitic and Ferritic stainless steels. They are Ferro-magnetic in nature and hardenable by heat treatment.

They possess moderate corrosion resistance and are identified in AISI 400 series.

HF-ERW pipes

HF-ERW pipes are made from hot rolled flat steel strip, formed into tubular shape and the longitudinal seam is welded by the application of mechanical squeezing of edges and heating the edges through High Frequency Electric Resistance applied by induction or conduction. The weld joint is achieved without addition of any filler metal.

Application Industry:

Oil and Gas Pipeline
Plumbing
Heating
Water Supply Systems
General purpose applications
Structural Pipe

FLANGES

Flanges

Codes to be refer for flanges are

B16.5 - dimensions and ratings of steel flanges NPS 24 and smaller

B16.47 series A - dimensions and ratings of steel flanges NPS 26 though NPS 60.

B16.47  series B used to mate existing equipment hole dimensions and PCD.

B16.36 - orifice Flange

Type of Flanges
Weld neck flange

Slip on Flange

Lap joint Flange

Socket weld Flange

Based on face of Flange classified as

Flat face  (FF)

Raised face (RF)

Ring Type Joint (RTJ)

Tong and Grove (T&G)

PIPING FIELD ENGINEER

Responsibilities of Piping field engineers

Provide technical assistance to WBS (Work breakdown structure) in-charge
and Area Manager and keeps them informed of all site activities.
Determine area priorities for piping installation
Communicate with piping design team to resolve piping design problem.
Review the project schedule.
Make priority of pipe spool, supports and valves to receive as per sequence of work.
Perform inspection of all piping work on continuing basis.
Assist area manager to solve piping problems.
Execute field take offs and provide input to project MTO (material take off).
Report completed quantity to Billing department.
Make priority of pipe spool, supports and valves to receive as per sequence of work.
Assist procurement team in the inspection and receipt of piping materials and in setting up project controls for storage and protection of piping materials.
Writes material requisitions for all pipe testing equipment, test blinds,gaskets,etc. required for the job.
Prepare JSA , method statement, Hazard and control procedure before erection to execute the job with all safety measures.

Casting and Forging

Casting is a process where metal is heated until molten. While in the molten or liquid state it is poured into a mold or vessel to create a design shape.

Forging is the application of thermal or mechanical energy to steel billets or ingots to cause the material to change shape while in a solid state

casting

We use castings for a wide range of wearparts and components that are too large, complicated, intricate or otherwise unsuitable for the forging process. We can forge parts up to 50kgs but the sheer energy required to forge large items make casting a much more viable alternative.

The advantages of casting include:

* No real upper size limit in casting weight
* Large range of alloy choices
* As forgings remain solid, custom alloys are far more difficult to get into production whereas with casting, alloys including Chrome, Nickel and Moly can be added at the molten stage
* Tooling is often less expensive than forge dies
* Smaller production ‘runs’ required
Complicated/complex parts are no problem
* For general GET as well as large and complex components – casting is a fantastic method of manufacture.

Forgings

Forging offers uniformity of composition and structure. Forging results in metallurgical recrystallization and grain refinement as a result of the thermal cycle and deformation process.

This strengthens the resulting steel product particularly in terms of impact and sheer strength.

Forge steel is generally stronger and more reliable than castings and plate steel due to the fact that the grain flows of the steel are altered, conforming the shape of the part.

The advantages of forging include:

* Generally tougher than alternative
Will handle impact better than casting
* The nature of forging excludes the occurence of porosity, shrinkage, cavities and cold pour issues
* The tight grain structure of forgings making it mechanically strong. There is less need for expensive alloys to attain high strength components
* The tight grain structure offers great wear resistance without the need to make products ‘superhard’. We have found that, on a blank HRC 38-42 forged grinder insert wear / wash is about the same as a high alloy HRC 46-50 cast grinder insert. The difference being a HRC46-50 casting does not have the ductility to handle high impact grinding.

Piping joints Handbook

 Piping joints Handbook 

 This book gives understanding about Pipe joint, pipe specification, Flange types and  specification. It gives details about selection of gaskets and its types and its  uses. It also gives details about bolting material and its specification and etc. One of the good book and very useful for piping field engineers. Go to the below link to find the book.

http://www.4shared.com/office/Ae5RtYo1/piping_joints_handbook.html

ASME B16 PIPING COMPONENT STANDARDS

• B16.1 cast iron pipe flanges and flanged fittings
• B16.3 Malleable iron threaded fittings
• B16.4 Gray Iron threaded fittings   
• B 16.5 Pipe flanges and flanged fittings NPS ½ - 24 INCH
• B 16.9 Factory made wrought butt welding fittings
• B16.10 Face to Face and End to End dimensions of valves
• B16.11 Forged fittings, socket welding and Threaded
• B16.21 Non metallic flat gasket for pipe flanges
• B16.25 Butt welding ends
• B16.34 valves flanged, Threaded and welding end
• B16.36 Orifice flanges
• B16.38 Large metallic valves for gas distribution
• B16.39 Malleable iron threaded pipe unions
• B16.47 Larger Diameter Steel Flanges NPS 26 – 60 Inch
• B16.48 Line Blanks   

PIPING CODES AND STANDARDS

Codes are used for the design, construction and inspection of piping systems.

ASME PIPING CODES 

B31.1 POWER PIPING

B31.3 PROCESS PIPING

B31.4 PIPELINE TRANSPORTATION SYSTEMS FOR LIQUID HYDROCARBONS

B31.5 REFRIGERATION PIPING

B31.8 GAS TRANSPORTATION & DISTRIBUTION PIPING

B31.9 BUILDING SERVICES PIPING

B31.11 SLURRY TRANSPORTATION PIPING SYSTEM

 

PIPING DEFINITION

        Pipe is a pressure tight cylinder used to convey fluid or transmit fluid pressure ordinarily designated pipe in applicable material specifications.

         Material designated tube or tubing in the specification are treated as pipe when intended to pressure service.

Piping is an assembly of piping components used to convey, distribute,mix,separate,meter,discharge,control or snub fluid flows.