PIPING MATERIALS

INTRODUCTION Piping materials are of many types. The specific material to suit a design requirement is chosen on the basis of certain key factors.

FACTORS AFFECTING SELECTION OF PIPING MATERIALSMechanical properties tensile, yield, creep, rupture, fatigue and impactPerformance requirements and material reliabilitySafetyEnvironmental conditionsAvailabilityResistance to erosion and corrosionEconomic factors

VITAL CHARACTERISTICS REQUIRED ToughnessCreep StrengthDuctilityGood surface finishHardness

CLASSIFICATION OF PIPING MATERIALS

COMMONLY USED PIPING MATERIALS LOW CARBON STEEL, LOW ALLOY STEEL AND STAINLESS STEELS(used for high temperature services)

WROUGHT IRON, CAST IRON, DUCTILE IRON, COPPER, BRASS, ALUMINIUM AND ITS ALLOYS AND NICKEL STEEL OTHER PLASTICS MATERIALS(PVC, polythene, polypropylene, asbestos cement, GR pipes, concrete, glass, rubber and some newer plastics)

TEMPERATURE LIMITATION OF PIPING MATERIALS

MATERIAL PROPERTIES

FERROUS MATERIALS

CARBON STEELSIs an alloy of Iron and CarbonContains 0.1 % to 1.5 % of CarbonBased on Carbon Content it can be classified into 1. Mild steel - 0.05 % - 0.30 % 2. Medium Carbon steel 0.30 % - 0.70 % 3. High carbon Steel 0.70 % - 1.5 % 4. It can withstand upto to a temperature of 450 CGeneral chemical composition of CS is C - 0.07, 1.56 %, Mn 1.6 %, Si 0.6 %, S 0.1%, P 0.1%.

CARBON STEEL MATERIAL COMPOSITION

Sheet1

MATERIALDESCRIPTIONCHEMICAL COMPOSTIONSERVICE

CMnSiPS

A106 GrBSeamless, CS pipe for high Temp & Pr services0.30.29 - 1.060.10.0350.035

(1/2-14)

API 5L GrBERW ( E=0.85), CS pipe, Seamless0.271.15-0.040.05

(1/2-14)

A53 GrBSeamless, CS pipe for low Temp services (Galv)0.30.90.15 - 040.0350.035Drinking water, instrument air

(1/2-14)

A105 (S.W.)Forged CS for ambient and high Temp services0.350.90.350.050.05Forged pipe fittings

(1/2-1)

A216GrWCBCS castings suitable for high Temp services0.310.60.040.045Cast valves

2 & above

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ALLOY STEELSAdding of Alloying elements to improve the characteristics of the material is termed as Alloy Steel.Commonly used Alloying elements are Silicon, Chromium, Nickel, Molybdenum, Manganese, Vanadium, Titanium, Boron, Aluminium, Cobalt and Tungsten.WHAT ARE THE EFFECTS OF ALLOYING?

PURPOSE OF ALLOYING 1. Improved Corrosion resistance 2. Better Hardenability 3. Improved Machinability High or low temperature Stability Ductility Toughness 4. Better Wear resistance

INFLUENCE OF ALLOYING ELEMENTS

Chart1

Sheet1

FoodGasMotel

Jan121710

Feb171121

Mar222914

Apr141017

May121710

Jun191520

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Alloying ElementAdvantageDisadvantage

AluminiumIncreases brittleness

(2 - 5 %)

ChromiumMachinability, weldability

Manganese

Molybdenum

(0.15 0.6 %)

NickelMachinability

(upto 5%)

Titanium

Tungsten

Vanadium

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LOW ALLOY STEEL MATERIAL COMPOSITION

Sheet1

MATERIALDESCRIPTIONCHEMICAL COMPOSTIONSERVICE

CMnSiCrMo

A335 GrP22Ferritic alloy steel pipe for high Temp services0.05 - 0.150.3 - 0.60.51.9 - 2.60.87 - 1.13HP, superheated and hot reheat Steam

A335 GrP910.08 - 0.120.3 - 0.60.2 - 0.58 - 9.50.85 - 1.05Superheated steam piping system

A234 GrWP22Pipe fitting alloy steel for moderate and elevated Temp0.05 - 0.150.3 - 0.60.51.9 - 2.60.87 - 1.13High Temp services

A217 GrWC9Alloy steel castings for Pr containing parts suitable for high Temp services0.180.4 - 0.70.62 - 2.750.9 - 1.2Valves for AS pipes

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STAINLESS STEEL Adding 11.5 % or greater chromium in iron,changes the microstructure and based on that its varieties are obtained. Posses greater percentage of chromium which forms a chromium oxide film exposed to air that prevents chemical attack of moist air on the material surface Nickel retains the austenitic structure of steel Greater resistance to corrosion than all types of steels Classified into three types based on its micro structure 1. Austenitic stainless steel 2. Ferritic stainless steel 3. Martensitic stainless steel

STAINLESS STEEL MATERIAL COMPOSITION

Sheet1

MATERIALDESCRIPTIONCHEMICAL COMPOSTIONSERVICE

CMnCrMoNi

A312 GrTP304Welded & seamless austenitic stainless steel0.035218-20-8 - 11Hydrocarbons, chemicals, etc.

A3120.271.1516-182-Mar11 - 14Corrosive process service

Gr.TP316L

(1/2-14)

A403Wrought austenitic stainless steel pipe fittings0.08218-20-8 - 11Forged fittings

Gr.WP304

A351Castings0.081.518-21-8 - 11Valve castings

Gr.CF8

A1820.08218-20-8 - 11Flanges

Gr.F304

(2 & above)

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NON-FERROUS MATERIALS

COPPER AND ITS ALLOYSUsed when heat and electric conductivity are importantTheraml conductivity is highAlloys are brasses, Bronzes (Cu-Sn) and Cupronickels (Cu-Ni)Upto 20% Zn in Brass gives good corrosion resistanceBronzes display good strength with corrsion resistanceCupronickels have highest corrosion resistance among Cu alloysCupronickels are used for heat exchanger tubing

NICKEL AND ITS ALLOYSEasy machinability and weldabilityChloromet and Hastelloy are widely used other than Monel 400Not resistant to oxidising environmentsMonel 400 is used to handle dilute sulphuric acid and hydrochloric acidAlkalis and sea water do not affect Nickel

ALUMINIUM AND ITS ALLOYSGood thermal conductivityMost workable metalHighly resistant to atmospheric conditions, industrial fumes, fresh brackish or salt waterNot resistant to corrosionLoses strength rapidly at 1750C.

TITANIUMStrong and medium weightTitanium Oxide is formed which prevents corrosionResistant to Nitric acid of all concentrations except fuming nitric acidWelding requires inert atmosphereLoses strength above 4000CProvides good resistance to hydrochloric acid when alloyed with 30% MolybdenumNot affected by impingement and crevice corrosion

COMMON NON-FERROUS PIPING MATERIALS (METALS)

NON-FERROUS MATERIALS COMPOSITION

NON-METALLIC PIPES

COMMONLY USED NON-METALLIC PIPING MATERIALSPlastics Thermoplastics and Thermosetting plasticsConcreteCeramicAsbestos-CementGlassRubber

THERMOPLASTICS

POLYVINYL CHLORIDE (PVC)Tough and exceptionally resistant to chemical attackRigid unplasticized Polyvinyl Chloride is thermoplastic materialPipes are manufactured by extrusionFittings, flanges and valves are manufactured by injection moulding

TYPES OF PVCThere are three types of PVC pipes, Type-I, normal-impact gradeType-II, high-impact gradeType-IV, newer grade

PVC MATERIAL PROPERTIES

ADVANTAGES OF PVC PIPESNo physical or little deterioration when exposed to direct sunlight, unlike other plasticsDoes not support combustionNo scales are formed over smooth inside surface

APPLICATIONS OF PVCExtensively used in highly corrosive application involving acids, alkalis, salt solution, alsohols and many chemicalIn oil fields as it can carry sour crude oil to which PVC is inert and paraffin built-up is minimumSalt-water disposal in oil fieldsGas transmission serviceCold water line in Industry as it is non-toxic and doesnt add any odour or taste to waterFor vent piping for removal of acid fumes and corrosive gases

TETRAFLUROETHYLENE (TEFLON)Unaffected by alkalis and acids except flourines and chlorines, molten metals at elevated temperatures (260 0C max)TFE + Chlorine = CTFE, which is highly resistant to corrosion by acids and alkalis up to 180 0C TFE components can be prepared only by powder metallurgy

POLYETHYLENE (PE)Produced from hydrocarbons and ethylene under high temperature and extremely high temperature pressureTypes Low, Medium and High DensityHDPE is not very flexible as LDPE2% Carbon black is added to increase weather resistance

APPLICATIONS OF PEHDPE is used in jet wells and farm sprinklersSalt water disposal linesChemical waste linesGas gathering systemsConduit for power and telephone cables

ACRYLONITRILE-BUTADIENE-STYRENE (ABS)It produced by injection or compression mouldingExhibit good toughness and tensile strength

APPLICATIONS OF PEService of inorganic acids, bases and saltsSewage pipingCrude oil and gas piping

THERMOSETTING PLASTICSGenerally produced by centrifugal casting, hand lay-up moulding and filament winding. Major resins are Epoxy and Polyester resins and generally reinforced with glass or blue asbestos fibre.

EPOXYUsed in transportation of acids, neutral or basic salt solutions, waste process water and sewageUsed in paper industries for pulp stock wastes and dyesIt resists fouling, salt atmosphere and marine organismUsed in food and beverage industry

CONCRETE PIPES

CONCRETE PIPING MATERIALSTypes reinforced and non-reinforcedSome non-reinforced concrete pipe material specifications are ASTM C14, AASHO M86, ASTM C412, etc.Non-reinforced pipe sizes vary from 12 to 24Some reinforced concrete pipe material specifications are ASTM C76, AASHO M170, SS-P-375, etc.Used for sewage and industrial waste, storm waste, culverts, water supply

ASBESTOS-CEMENT PIPESNot used very commonlySome standard material specification are ASTM C296, AWWA C400, SS-P-331, etc.Used for drains and industrial waste

PIPE LININGS

COMMONLY USED LINING MATERIALSRubberPlasticLeadGlassEpoxy resinSynthetic resin

RUBBER LINED PIPESNatural and Synthetic rubber linings are used to counteract corrosionGenerally used in the temperature range of 20 OC to 50 OCCommonly used natural rubbers are soft rubber, semi-hard and hard rubbersCommonly used synthetic rubbers are Polychloroprene-Neoprene, Butyl rubber, Nitrile rubber and ThiokolCannot be used for strongly oxidising conditions or halogenated carbon

PLASTIC LININGPTFE and PVC are important lining materialsUsed for chemical resistance, corrosion protection, resist abrasion, non-toxic and smooth bore reduces friction PTFE is chemically inert and used from 270 OC to 260 OCPolyvinyl flouride, fluoroethylene propylene and polypropylene can be added to enhance the range of PTFEPVC provides tough and heavy-duty finish resistant to most acid and marine growth

LEAD LININGSLead lining is useful for most corrosive fluids and sulphuric acid below 80% concentrationShould not be used for nitric acid, hydrochloric acids, hydrofluoric acids, organic acids and alkalisCan be alloyed to improve mechanical properties

GLASS LININGSGlass enamel (glass like) inorganic compositions are used as liningsBonded to mild steel by fusion on metal surface above 750 OCProvide good resistance against acid attack and abrasionCheap alternative in many situationsTemperature range of 20 OC to 250 OC

EPOXY RESIN LININGSGood resistance to alkalis and most acids except strongly oxidising onesGood resistance to abrasion by suspended particles due to glossy nature of liningUsed mostly in natural gas pipe lines

SYNTHETIC RESIN LININGSSprayed phenol formaldehyde can be used when expected corrosion is lessCannot be used above 80 OCBecause of sterile and non-tainting properties it is used in food processing industriesMostly used to line welded steel vessels

LINED PIPES SAMPLES

PIPING MATERIAL SPECIFICATION

What is a Material Specification? A Piping Material Specification is an engineering specification that contains requirements for the selection of materials to be used in the construction and fabrication for all process and utility piping.

FEATURES OF A MATERIAL SPECIFICATIONMaterial of construction, end construction, end connections and wall thicknesses for various rangesIndividual line class of the piping materialsCodes and standards relevant to the pipes and fittings of the specified material classLine class coding systemPressure-Temperature ratings for various fittings and limiting sizes of fittingsOther general notes and design criteria as applicable to the material class

CLASS SERVICE INDEX IDEA STANDARDS

SOME MATERIAL COMPARISONS

GENERAL DESIGN CONSIDERATIONS Seamless pipes are mostly preferred in power piping, butt welded may also be used API 5L pipes are not permitted by IBR for design pr.>20 kgcm2 and temp>260 OC Most projects require multinational specification Economy precedes the choice of code for material specification, after design requirements

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