– Brief Presentation –

DUCTILE IRON SPUN PIPE – Brief Presentation – Technical Presentation Electrosteel Castings Limited 4, B. B. D. Bag (East), Calcutta – 700 001

PIPE MATERIAL – BASIS OF SELECTION Desired properties: • Structurally strong • Fast and easy laying • No / Minimum Maintenance • Bottle-tight and Flexible Jointing System • Ability to resist “Corrosion” • Tamper-proof THE ANSWER IS CENTIFUGALLY CAST INSIDE CEMENT MORTAR LINED DUCTILE IRON PIPE ELECTROSTEEL CASTINGS LIMITED

WHAT IS DUCTILE IRON (DI)? Cast Iron Corrosion Resistant but Brittle Mild Steel Strong but Corrosion Prone Ductile Iron Corrosion Resistant + Strong ELECTROSTEEL CASTINGS LIMITED

WHAT IS DUCTILE IRON? In 1949, a process was invented by which flaky graphite in cast iron could be changed to nodular graphite by adding little magnesium in molten iron. The nodular graphite helps to maintain the continuity of iron matrix providing excellent properties of flexibility, ductility and impact resistance. Grey Iron Ductile Iron ELECTROSTEEL CASTINGS LIMITED

DUCTILE IRON PIPE – ADVANTAGES  Better physical and mechanical properties compared to other pipe materials: • High tensile and beam strength • Withstands severe crushing load • Extremely high impact resistance  More water carrying capacity, as internal diameter is greater than nominal diameter.  Highly corrosion resistant due to smooth inside cement mortar lining, thus offering a higher C value (HWC = 140), corresponding Darcy’s Friction Factor (f = 0.012).  The ISO, BS, DIN and IS specifications are identical. ELECTROSTEEL CASTINGS LIMITED

DUCTILE IRON PIPE – ADVANTAGES  Offers high working pressure and safety against water hammer - Every DI pipe is hydrostatically tested to a minimum of 40 kg./cm2 before application of lining and coating. • Speedy Laying / Installation procedure.  Ease in handling – Light weight and superior mechanical property makes DI pipe easier to handle.  Welding is possible.  Offers impressive energy savings, due to less frictional losses.  Offers a virtually maintenance free pipeline. ELECTROSTEEL CASTINGS LIMITED

MACHINABILITY – DI PIPE Cutting Tapping Welding ELECTROSTEEL CASTINGS LIMITED

COMPARISON OF DI, CI & MS PIPES Mechanical Properties ELECTROSTEEL CASTINGS LIMITED

Type Test What Is Type Test? Type Test is testing the pipe and pipe joint at extreme working conditions (the product and use) to ensure satisfactory performance. The recommended Type Tests as per BS EN 545/598, ISO: 2531 are: • Leak Tightness of Joints to Positive and Negative Internal Pressure • Leak Tightness of Joints to Positive External Pressure • Test for Abrasion Resistance • Test for Chemical Resistance to Effluents ELECTROSTEEL CASTINGS LIMITED

Type Test Leak Tightness Of Joints To Positive And Negative Internal Pressure  Spigot end is machined to minimum.  Socket opening is machined to maximum.  Joint assembled with gasket and a shear load is applied on the spigot end.  Joint is tested at a higher pressure than the works test pressure with and without joint deflection. ELECTROSTEEL CASTINGS LIMITED

Type Test Initiatives At ECL Leak Tightness Of Joints To Positive And Negative Internal Pressure Without Joint Deflection With Joint Deflection ELECTROSTEEL CASTINGS LIMITED

Type Test Initiatives At ECL Type Test Results I = Leak tightness of joints to positive internal pressure (without deflection) I (4.50) = Leak tightness of joints to positive internal pressure (with deflection) II = Leak tightness of joints to positive and negative external pressure ELECTROSTEEL CASTINGS LIMITED

Type Test Leak Tightness Of Joints To Positive External Pressure  The test assembly shall comprise of 2 joints made with 2 pipe sockets welded together.  It creates an annular chamber which allows testing of one joint under internal pressure and one joint under external pressure.  The assembly is tested at a pressure of 2 bar for 2 hours to ensure that contaminated water cannot enter through joint even when there is no inside pressure. ELECTROSTEEL CASTINGS LIMITED

Type Test Test For Abrasion Resistance  This test is meant for DI Pipe with High Alumina Cement Lining specially meant for sewerage applications.  1 m. long pipe sample, closed at both ends is filled with gravel.  The gravels are allowed to slide over the cement surface for 1 lakh cycles and resulting abrasion is observed. It has been observed that High Alumina Cement Mortar Lining has better abrasion quality than bare metal. ELECTROSTEEL CASTINGS LIMITED

Type Test Initiatives At ECL Test For Abrasion Resistance ELECTROSTEEL CASTINGS LIMITED

Type Test Test For Chemical Resistance To Effluents  This test is meant for DI Pipe with High Alumina Cement Lining specially meant for sewerage applications.  Pipe sample is filled up to mid height with Sulphuric Acid solution at pH 3.  Another Pipe sample is filled up to mid height with Sodium Hydroxide at pH 13.  The samples are observed for 6 months. ELECTROSTEEL CASTINGS LIMITED

HOW CORROSION AFFECTS PIPES Unlined Cast Iron Pipe Installed in Calcutta 25 – 30 years back Condition monitored In November, 2000 ELECTROSTEEL CASTINGS LIMITED

COMPARATIVE CORROSION OF METALLIC PIPES Critical Elements In Iron & Steel Pipe (All Figures Shown Above Indicates %age Weight) The volume impurities : CI/DI : 17.0 – 18.5% MS : 1.1%. 15.5 times more surface area in CI / DI is occupied by non-ferrous species compared to MS. Hence less surface area open to CI / DI for corrosion. ELECTROSTEEL CASTINGS LIMITED

ACCELERATED CORROSION TEST Results Of Dipping Test With Sea Water Increasing rate of corrosion with time Decreasing rate of corrosion with time Volume Of Corrosion (mg./dm2/day) ELECTROSTEEL CASTINGS LIMITED

MS Pipe – Mandatory Wrapping & Coating Excerpts From IS : 10221 – 1982 Code Of Practice For Coating And Wrapping Of Underground Mild Steel Pipes ELECTROSTEEL CASTINGS LIMITED

DI PIPE – CORROSION PROTECTION Internal Corrosion Resistance  In order to enhance internal corrosion protection, all Ductile Iron Pipes come with Internal Cement Mortar Lining. External Corrosion Resistance  All pipes come with a layer of metallic zinc and a finishing layer of bituminous paint. The following additional external corrosion systems are also available  External polyethylene sleeving  Epoxy paint coating The type of protection depends on soil condition ELECTROSTEEL CASTINGS LIMITED

BITUMEN LAYER ZINC COATING IRON OXIDE LAYER DUCTILE IRON CEMENT MORTAR LINING DI PIPE – CORROSION PROTECTION Corrosion Protection Systems ELECTROSTEEL CASTINGS LIMITED

ZINC COATING - EXTRA CARE How Zinc Coating Helps to Prevent Surface Corrosion # When pipe is buried,the zinc coating transforms into a dense,impermeable layer of Zinc Oxide and salts. ##The metal exposed becomes cathodic to the rest of the zinc coated surface area which acts as an anode ELECTROSTEEL CASTINGS LIMITED

DUCTILE IRON PIPES – BURSTING STRENGTH P1 = Bursting Strength based on Net Wall Thickness (Bar) P2 = Bursting Strength based on Minimum Wall Thickness (Bar) BP – Bursting Pressure MOP – Maximum Operating Pressure AOP – Allowable Maximum Operating Pressure ELECTROSTEEL CASTINGS LIMITED

ADVANTAGES OF CML • CML provides higher Hazen William’s C value. DI CML has a C value of 140 in comparison to 100 for bare metallic pipes. • Due to higher C value pumping costs get reduced. • CML permanently increases carrying capacity. • CML passivates the pipe wall by the alkaline reaction of cement. • CML prevents pitting and tuberculation of metallic pipes and there by stops the production of red water. • The prevention of internal corrosion by CML helps to maintain same flow area and flow friction co- efficient over a long period of time. • Prevents abrasion of pipe wall and thus increases life of pipe. ELECTROSTEEL CASTINGS LIMITED

BONDING STRENGTH OF CML • No CML failure has ever been recorded in negative surge. • Longitudinal bending tests demonstrates the ability of the cement mortar lining to follow wall deflection as long as the metal remains in the elastic range. • The maximum allowed service deflection is 3% of initial diameter. In ‘Ring Bending Test’, it has been observed that disbonding do not occur until deflection reaches 7- 12% of the initial diameter. ELECTROSTEEL CASTINGS LIMITED

AUTO – HEALING OF CRACKS • Cracks / fissures in CML are common. Cracks up to 0.8 mm. width is allowed in all the standards (IS, EN or ISO). • Tests had shown that lining cracks/fissures, will heal when line is charged. Details of these test is documented by ISO in their Document No. ISO/TC 5/SC 2 N 382E. • When a cement lined pipe is filled with water, some water is absorbed by the pores and voids in the mortar, as also by the capillary channels of the Calcium Silicate gel. • As a result the lining swells practically to its initial volume. and the cracks in the lining are closed. ELECTROSTEEL CASTINGS LIMITED

DUCTILE IRON (DI) PIPE Cement Mortar Lining Recommended Types Of Cement ELECTROSTEEL CASTINGS LIMITED

JOINT SAFETY OF DI PIPES IN UNSTABLE SOIL How DI Pipes offer more safety to design ? Sudden Soil Movement in unstable ground. General ground contour followed by pipe line • Ductile Iron Pipes with flexible joints are capable of angular deflection, allowing the pipeline to follow ground contour • A Japanese study in 1979 following the Miyagi – ken – Oki earthquake showed a 0.04 damage rate / km for DI pipes compared to four times that of grey iron and more than 30 times that of other materials. ELECTROSTEEL CASTINGS LIMITED

Electrosteel Castings Ltd.

– Brief Presentation –