June 28, 2017 By Waverley Brownall

Corrosion Concerns In Oil And Gas Production

Areas of corrosion concern and consideration within the Oil and Gas production industry:

• Pipeline pressure vessel steels for resistance to Hydrogen Induced cracking
• Application of thermal spray coatings (aluminium, zinc and other alloy composites)
• Laboratory testing of metals for resistance to sulphide stress cracking
• Preparation, installation and analysis of corrosion in oilfield operations
• Corrosion control in submerged areas of steel offshore structures (petroleum production)
• Corrosion control of offshore structures with use of protective coatings
• Bacterial growth reporting for oil and gas systems
• Atmospheric and splash concern for offshore zones
• Corrosion control in injection systems – particularly in seawater
• Corrosion control of tubular goods within oil and gas environments
• Evaluation reports concerning pipeline and pressure vessel steels

Visit NACE.org for standards and reports, including specific reports for applications not listed above.

Corrosion by category

Types of corrosion can usually be separated into three separate groups.

1) The first group consists of corrosion types that can be seen with ordinary visual examination. These types of corrosion include pack rust, crevice, galvanic and pitting corrosion.

2) The second group includes corrosion types that may require further inspection or testing to define corrosion presence. The second group consists of corrosion such as erosion, exfoliation, fretting and cavitation.

3) The third group will require verification by microscopy, including environmental cracking, fatigue and SCC.

Corrosion resistance and product longevity

Of course, the most common control methods of controlling corrosion includes protective coatings, but even these are at risk of wearing over long periods of time.

For areas of which need longevity above most, such as offshore platforms, something with a stronger resistance is required.

Due to the nature of applications within the Oil and Gas production, one of the best corrosion control methods is within the initial material selection of the fittings, pipelines, valves and instrumentation that is going to be used.

Although no metal is completely resistant to all corrosive natures, NACE advocate that ‘materials selection is critical to preventing many types of failures’.

Looking for corrosion resistant tube, valves or fittings? Speak to our team today
enquiries@waverleybrownall.co.uk

Helpful links:

· Special Metals

· How to solve pipe fitting corrosion

· Corrosion in the Oil and Gas industry

· Corrosion control in Oil and Gas pipelines

· Corrosion in the Oil industry

· Metallurgy and Corrosion Control in Oil and Gas production

· Corrosion basics NACE international

November 3, 2016 By Waverley Brownall

Tube Fittings Material Selection

Tube fittings material selection can be a tricky process, where cost and availability are at the forefront for many industries.

Quick tip: Charts for aqueous corrosion resistance and material composition can be found on our special metals page.

Tube Fittings Material Selection

All products from our compression Tube fittings (single and double) range are available in special metals.

Other products that can be manufactured include pipe fittings for high or low pressure applications and valves for full flow control of media.

Material	Features	Availability
316 Stainless Steel	Most commonly specified material for a range of environments	Immediate with next day delivery
6MO Stainless Steel	Pitting, crevice corrosion and strength increased from 316	Moderate stocks
Monel 400	Great choice for general seawater application. Popular with pump manufacturers.	Moderate stocks
Duplex SS	A natural step-up from 316 and 6MO	Moderate stocks
Super Duplex SS	Fantastic atmospheric corrosion	Moderate stocks
Incoloy 825	Outstanding resistance in reducing environments, used extensively in chemical processing	Immediate and Moderate
Inconel 625	High strength, excellent corrosion resistance and welding abilities	Deliveries less than 8 weeks
Hastelloy C276	Outstanding corrosion resistance. Almost unmatched in seawater application especially under crevice conditions which would attack 316, 6MO and Monel 400.	Immediate for popular size fittings and Moderate material stock
Titanium	Excellent strength, corrosion resistance and used extensively in the aerospace and automotive industries. Outstanding all-round resistances.	Manufacture-to-order, no more than 6 weeks

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Tube Material Selection

Tubing Material	General Application	Rec. Temp Range*
316 Stainless Steel	High pressure, High Temperature, Generally Corrosive Media	-225C to 605C
Monel 400	Recommended in Sour Gas, Marine and Chemical application	-198C to 425C
Hastelloy C-276	Excellent corrosion resistance to Oxidizing and Reducing Media	-198C to 535C
Titanium	Resistant to Many Natural Environments such as Seawater and Salt solutions	-59C to 315C

Main Considerations When Selection The Right Material

Media (Internal)
Environment (External)
Intended Application and Process
Strengths and possible Weaknesses
Cost effectiveness (Selecting a special metal over 316 stainless steel is often considered a long-term investment. Costs for maintenance are dramatically reduced.)
Availability
Health and Safety Regulations

Corrosive Environments

Possible corrosive environments are a key factor for the durability of tube fittings and pipe fittings. Certain materials will cope better than others when faced with the different types of corrosion.

You will need to find out the effectiveness of the materials you are considering for your fittings against main consideration factors. (Media, environment, strengths, cost effectiveness, availability, safety…)

Corrosion By Acids

*Chart is to be used as a guideline only. Please discuss with us the internal media and external environment for your tube and pipe instrumentation.

Acidic Media	Resistance Material Choices
Sulphuric	6M0 (When the temperature is moderate and concentration is over 65%) Incoloy 825 (Good general resistance) Hastelloy C276 or Inconel 625 (At higher temperature ranges)
Hydrochloric	6M0 (Diluted) Incoloy 825 (Diluted) Inconel 625 (Diluted) Hastelloy C276 (The best choice with aggressive solutions)
Phosphoric	6M0 (Pure phosphoric) Incoloy 825 (Recommended – holds resistance to pure phosphoric at all concentrations and temperatures up to boiling 85%) Hastelloy C276 and Inconel 625 (In the presence of chlorides and fluorides)
Nitric	Incoloy 825 (Resistance to solutions up to boiling 65%) Inconel 625 Titanium

The Main Considerations In Acidic Corrosion Resistance

Concentration of the acid
Working temperatures and aeration
Inclusion of any other medias
The external environment
Dilution methods
Surrounding health and safety considerations

*Information provided in this blog post are to be used for general material selection guidance only. We recommend you speak to one of our specialists for applying your special metal tube, fittings and valves for the working application.

enquiries@waverleybrownall.co.uk

DON’T MISS OUT

With Waverley Brownall’s vast choice of tube fittings, pipe fittings and valves – you will be sure to find what you need with us.

Common thread types include NPTF, BSP, BSPT and BSPP.

In sizes up to 2″ for standard fittings,
materials include all listed in this post.

October 20, 2016 By Waverley Brownall

5 Common Types Of Corrosion

Common types of corrosion that are seen within industrial, marine/offshore and oil and gas include 5 main categories. These are what we will cover in this blog post, including suggestions on how to prevent it.

Metals that are attacked by corrosive substances are open to damage that can effect the durability and safety of the alloy. This is a huge concern for sectors of industry with environmental considerations. For example, within the marine and offshore industries, engineers will require metals that can withstand exposure to seawater.

Common Types Of Corrosion

1. Galvanic Corrosion

Galvanic corrosion will occur when two separate metals/alloys are in contact with each other. This type of corrosion will occur when

a) When metals are electrochemically dissimilar

b) Metals are in electrical contact

c) Metals are exposed to electrolyte

2. Uniform Corrosion

Irons and steels will corrode in ‘uniform’ when exposed to certain environments such as soils and natural waters. Rust will appear in the presence of uniform corrosion.

3. Pitting Corrosion

Spots and pits will appear on the metal with this type of corrosion. It is a type of localised corrosion, which means that the attack is accelerated due to exposure of an area on the metal that an otherwise protective coating or layer has broken down.

4. Stress Corrosion Cracking

Unexpected sudden failure can occur with this type of corrosion. Attack of an alloys tensile strengths at high temperatures is a common situation for stress-corrosion cracking.

5. Aqueous Corrosion

“Aqueous corrosion is an electrochemical reaction of materials due to a wet environment, resulting in the deterioration of the material and its vital properties.” – What Is Aqueous Corrosion by Corrosionpedia.com

Corrosion Prevention

There are various ways to prevent the effects of corrosion. Each type of corrosion will differ in the prevention method.

However, generally, the selection of the correct corrosion resistant metal to begin with can prevent needing further treatments and prevention methods.

some prevention methods that need consistent updating and maintenance can be a hassle – both economically and practically. An investment of a high-performance alloy will save much of this hassle.

It is very important to note that each corrosion resistant metal has its own properties and composition that will cope with some types of corrosion better than another.

This is why the selection of the right material is vital for cost, availability and most importantly – safety.

Material Selection And Advice

Corrosion Problem	Solution
Galvanic Corrosion	Avoid mixing fittings and valves wherever possible
Uniform Corrosion	Limit or prevent this by an appropriate choice of alloy
Pitting Corrosion	High resistance to pitting will be a crucial consideration point for any alloy
Stress Corrosion Cracking	Avoid surface machining stresses. Stress cracking resistance needed.
Aqueous Corrosion	Metals with fantastic seawater resistance Eg. Inconel 625

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Includes:
– Corrosion Resistance Charts
-Availability and Costing
-Delivery and Manufacture
-Material properties
Monel 400, Incoloy, Inconel, Hastelloy and more

More Information:

Special Metals

Eight Forms Of Corrosion list by CorrosionDoctors.org

Types Of Corrosion by Merinox