November 3, 2017 By Waverley Brownall

6 Alloys With Aqueous Corrosion Resistance

Aqueous corrosion resistance; the key to better sleep for every marine engineer!

If you’re looking for an alloy with outstanding resistance to aqueous corrosion, the below six are some of the best alloys on the market.

All alloys listed have incredible resistance to various forms of aqueous corrosion, including acids such as Sulfuric, Hydrofluoric, Nitric, Hydrochloric, salts, and seawater.

INCONEL® Alloy 22

Alloy 22, also known as Nickel alloy 22 or Hastelloy C-22, this high-grade alloy offers a wide variety of corrosion resistance. Its aqueous corrosion resistance is known as a top choice for resistance at higher temperatures. This alloy is used frequently for processing nuclear fuel and, thanks to its resistance to seawater, general marine industries.

INCONEL® Alloy 625

This nickel-chromium alloy offers high strength and thermal strength, resistance to oxidation and resistance in a large range of temperatures. This INCONEL alloy is known for its versatility which makes it a great choice for within a number of industries. It is known for its incredible heat-resistance, up to 815°C cryogenic temperatures. Inconel 625 has proven indispensable within the aerospace and marine industries.

INCONEL® Alloy 625LCF

This version of 625(LCF – Low Cycle Fatigue) is specifically designed with low cycle fatigue resistance at temperatures up to 649°C. Apart from the LCF benefits, this alloy holds properties similar to alloy 625 because of such a closely related chemical composition.

INCONEL® Alloy 686

Used mostly in areas of extreme corrosion – classed as a “super alloy”, Inconel 686 provides function at high temperatures and stresses. With a content of 59% Nickel, 19-23% Chromium and up to 17% Molybdenum on average, it can handle up to 104700 psi (tensile strength.)

INCONEL® Alloy G-3

Alloy G-3 is a nickel-chromium-iron alloy that has good weldability and resistances to intergranular corrosion. It is commonly used for dealing with phosphoric and sulfuric acids in particular. Another alloy developed by Special Metals Corporation, it has a low carbon content and high resistance to atmospheric and acid corrosion. It is machinable with use of high-speed tools at a continuous pace to avoid work-hardening.

INCOLOY® Alloy 825

Alloy 825, (along with Inconel 625) is one of the most popular choices of alloy for resisting corrosive substances. Most Incoloy’s in the 800 series, such as 800, 800H and 800HT are known for their incredible heat resistance, especially in treatment plants, pipelines, and tubing. Incoloy 825 is just as impressive, giving fantastic overall resistances, with high strength and resistance against stress-cracking, pitting and intergranular corrosion.

We recommend 825 for customers requiring a material that lives up to the “super alloy” name, particularly within petrochemical, oil and gas, pollution and processing industries.

Waverley Brownall manufacture fittings, components and valves from INCONEL® and INCOLOY® Special Metals materials for engineers within the UK and around the world.

November 21, 2016 By Waverley Brownall

5 Impressive Corrosive Resistant Alloys

Corrosion is described as, “A natural but controllable process” by Gretchen Jacobson (Managing Editor of Materials Performance for NACE International.)

It is a naturally occurring problem, the deterioration of materials due to chemical reactions in the surrounding environment.

Corrosive Resistant Alloys

1. 6Mo Austenitic Stainless Steel (UNS S31266)

The metal 6Mo is often referred to as super-austenitic. This type of stainless steel covers grades with high chromium, nickel and molybdenum content. 6Mo is an alloy that was designed specifically for metallurgical stability and resistance against corrosive substances.

Strengths: Seawater and Organic acids

2. Inconel 625 (UNS N06625)

Strengths: Organic acids, alkaline and salts, seawater, sulfuric and nitric acid

3. Hastelloy C-276 (UNS N10276)

Strengths: Organic acids, alkaline and salts, seawater, sulphuric acid, hydrochloric, hydrofluoric and phosphorus acid, chlorine (wet).

4. Titanium (Grade 2 | UNS R50400)

Strengths: Chlorine (wet), uses for strength to weight ratio, alkaline, salts and seawater.

5. Monel 400 or Alloy 400 (UNS N04400)

Strengths: Seawater, salts and hydrofluoric acid.

Learn more…

The Fight Against Corrosion

Corrosion is a problem for many industries, including the Department of Defence, Energy, Oil and Gas production and transfer – including pipelines.

The industry of water and wastewater is also affected; both public and private companies must protect assets against corrosion.

These assets are main parts of the infrastructure for wastewater plants, such as reservoirs, pumping plants and distribution pipelines – even storage.

The materials that are used in order to fight corrosive media is essential for preventing system failures and other hazardous matters.

If you’re interested in the topic of how to prevent corrosion, check out the links below.

Corrosion Concerns In Oil And Gas Production

Inconel 625 Tubing UK Suppliers

Titanium Components Supplied To The Aerospace Industry

Inconel 625 Oxidation Resistance

Inconel 625 oxidation resistance is higher than that of other alloys. It is one of the many reasons that this alloy[…]

Nitric Acid Resistant Materials

Alloy 625 Tubing | 625 Tube Sizes & UK Supply

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.