pitting corrosion - pac · pdf filepitting & crevice corrosion grinding debris from work...

Pitting Corrosion

Pitting & Crevice Corrosion

Grinding debris from work carried above a tube run that has initiated Pitting Corrosion on Duplex material..

Pitting & Crevice Corrosion

Note the Crevice Corrosion on this 2507 material at the back of the fitting & on the tube.

Crevice Corrosion Under Clamps

Pitting & Crevice Corrosion

316 Metal on metal – not a good idea. Note the 2 points of Crevice Corrosion where the clamp makes contact with the tube

316 Stainless Steel Time to Failure

“316 Stainless tube failed after 2 years on a new Tug Boat” Malcolm Parratt, New Build Superintendent, Swire Offshore. “The 316 Stainless Steel tube failed on the Bonga FPSO after 18 months in service” Yemi Okeremi, Senior corrosion Engineer at Shell.

316 Stainless Steel Time to Failure

“In the past 3 years alone, dozens of in-service tubing failures in small-bore 316L SS tubing have been reported on most BP-operated GoM deep-water installations. The vast majority of these incidents are attributed to external corrosion, the cause of which is due to the susceptibility of 300-series austenitic stainless steels to crevice and pitting corrosion in marine atmospheric environments. Other BP locations (e.g., North Sea, Trinidad), major oil and gas producers, and other sectors such as the NASA and the military have had similar historical and recent experience with chronic external corrosion of Type 316L SS tubing. This problem not only results in service disruptions and increasingly expensive maintenance and repair, but poses potentially significant risks to health, safety, and the environment if not effectively mitigated and/or prevented.” Ardjan Kopliku – BP Corrosion Lead -GoM

Pitting & Crevice Corrosion Super Duplex Alloys

Crevice Corrosion on 2507 tubing accelerated by the 316 clamp “fingers” separating the tube.

Crevice Corrosion

Despite more than 10 years marine exposure on a Shell semi submersible support vessel the exposed surface of a section of Tungum Alloy Tube remains clear of corrosion. The Stainless steel Section from a Southern North Sea gas platform in the Leman field shows crevice corrosion after barely 4 years in the same environment.

Crevice Corrosion on 316 St.Steel under the clamps.

Total Lifetime Capital Cost based on 30 Years

Oil & Gas- HP control lines <5,000 psi

Tungum tube runs (gold colour) showing standard working practices for clamping & bend radius’s

Oil & Gas- Safety Shut Down Conduit

Tungum tube runs used as a corrosion resisting conduit for wire rope

90° Pulleys

Oil & Gas- Clamping Arrangements

Tungum tube runs (gold colour) showing standard working practices for using St.Steel twin ferule fittings & 3x Dia. bend radius’s . However, not a good idea to have 2 tube runs tight side by side. Leave a 5mm minimum gap where possible.

Oil & Gas- HP Lines Twin Ferrule Fittings

Tungum tube runs (gold colour) showing standard working practices for using St.Steel twin ferule fittings & 3x Dia. bend radius’s

Dive Systems – Tungum for O₂ Service

Oxygen Compatible Systems – Hyperbaric Chamber

Military Fighting Vehicles, Hydraulic Lines

Transport – Brake Line Systems

Typical End Users & Specifiers

Tungum Protective Oxide Layer

Tungum’s protective oxide layer polished back to reveal that no crevice corrosion has occurred under the pipe clamp.

Tungum Protective Oxide Layer

Tungum tube used for Temperature Safety Element (TSE) loops in service for 15 years. Note the green verdigris oxide layer, on the tube. This is to be expected after this period of time and is part of the tubes protective system.

Tungum Protective Oxide Layer

Tungum tube showing the green verdigris oxide layer after 15 years in service with no galvanic corrosion issues with the St.Steel fittings into the bulkhead.

Hydraulic lines <5,000 psi

Pneumatic lines <5,000 psi

TSE Loops

Sea Water – Flow rate < 4-5 mtr per/sec

Pressure sensing lines

Potable water lines

Grey & black water

Chemical injection lines – Caution, solution compatibility

Diesel / fuel lines

Oxygen lines

Conduit tubing- Emergency shut down systems

Important note – Avoid applications with Acetylene Ammonia & Mercury

Applications in Oil & Gas Non-Process

Excellent lifetime cost compared to other tubing options

No recorded failures of Tungum tube when correctly used and installed

Compatible and approved with all industry recognised tube fittings

Quicker installation times - can be as little as 75% of the time compared to Super Duplex or Austenitic St.Steels

Reduced system down times due to its longer life

Material of choice for Oxygen and hyperbaric systems

Over 30 years of experience of real time Oil & Gas applications

Key benefits

ISO9001:2008 Approval

ASTM B706-00 Temper TF00 “Seamless Copper Alloy (UNS No. C69100) Pipe and Tube”

BS EN 12449-CW700R-R430 “Copper and Copper Alloys-Seamless, Round Tubes for General Purposes”

ASTM G124-10 “Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres”

ASME B31.1 and B31.3 USCG – United States Coast Guard

Identified as ALLOY CZ127

In-house specification TCL100

Ministry of Defence specifications:

Aviation: DTD5019 (for high pressure systems)

DTD253A (for low pressure systems)

Navy: NES749 part 3

Army: AFS4000

Specifications

Chemical Composition

Element Min % Max%

Copper 81.00 84.00

Aluminium 0.70 1.20

Nickel 0.80 1.40

Silicon 0.80 1.30

Iron 0.25

Lead 0.05

Tin 0.10

Manganese 0.10

Total Other 0.50

Zinc The Remainder

Physical Properties

Mean Ultimate Tensile Strength 480 N/mm²

(31.07 tons per Sq. in.)

Mean 0.2% Proof Stress 240 N/mm²

(15.54 tons per Sq. in.)

Design Stress at 4:1 Safety Factor 107.5 N/mm²

(6.96 tons per Sq. in.)

Hardness 140 HV5 max.

Elongation (Average) 45 Per Cent

Magnetic Permeability 1.0015µ Max.

Thermal Conductivity at 300 K 1.0W/cm K.

Weight 8.52 x 10 kg/mm³

(0.308 lbs per cu.in.)

Typical material test cert

Family owned UK Limited Company

Established in 1933

World wide distributor network

World wide approvals and certifications

Tungum Limited

Tungum Worldwide

PAC Stainless USA www.pacstainlessltd.com

Global Hydraulic Singapore www.globalhydraulics.com.sg Stauff –Korea Korea www.stauff.com

Items AB Sweden www.itemsab.com

Fernandez Jove S.A. Spain www.fernandezjove.com

Petrotech LLC Middle East www.petrotech.ae

Hydrasun Ltd Scotland, www.hydrasun.com Netherlands & Caspian Sea countries.