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Corrosion Coupons


Corrosion couponsAccurate monitoring of corrosion rates in any environment is critical when viewed in terms of the maintenance and repair costs associated with corrosion and material failure. Test coupons provide an inexpensive means of on-line monitoring that will allow you to effectively measure the corrosivity within your system. By observing the mils-per-year corrosion rate of an exposed coupon, valuable information can be provided regarding the material's life expectancy.

Metal Samples can make coupons in any size, shape, or material you need. Coupons can be stenciled with alloy and sequence numbers for proper identification. Mill test reports, identifying element compositions of materials used, are provided on all orders.

Corrosion coupons
Coupon after being exposed to corrosive environment.

The following coupons are four of the most commonly used in corrosion testing.
Custom coupon sizes available.

P/N CO100

P/N CO131

Corrosion coupons Corrosion coupons
Shape Rectangular
Finish Double disc or glass bead
Identification Stenciled - alloy, heat no., sequence
Surface Area 3.38 in2
Shape Rectangular
Finish 120 grit, glass bead, or mill
Identification Stenciled - alloy, heat no., sequence
Surface Area 3.47 in2

P/N CO146

P/N CO220

Corrosion coupons Corrosion coupons
Shape Rectangular
Finish Glass bead or mill
Identification Stenciled - alloy, heat no., sequence
Surface Area 4.26 in2
Shape Circular
Finish 120 grit, glass bead, or mill
Identification Stenciled - alloy, heat no., sequence
Surface Area 2.72 in2

Flat Coupons

corrosion coupons

P/N Size Hole Hole Location Area Sq. In.
CO100 1/2" X 3" X 1/16" 3/16" 1/4" fr. end 3.38
CO101 1" X 2" X 1/16" 3/16" 1/4" fr. end 4.32
CO102 1/2" X 3" X 1/16" 9/64" 1/8" fr. end 3.41
CO103 1/2" X 3" X 1/16" 1/4" 1/4" fr. end 3.34
CO104 1/2" X 3" X 1/16" (2) 1/4" 1/2" fr. ea. end 3.24
CO105 1/2" X 3" X 1/16" 3/16" 1/2" fr. end 3.38
CO106 1/2" X 3" X 1/16" 1/4" 1/2" fr. end 3.34
CO115 1/2" X 3" X 1/16" 1/4" 1/4" fr. end 7777
CO117 3/8" X 3" X 1/16" 9/64" 1/8" fr. end 2.64
CO118 1/2" X 3" X 1/16" (2) 1/4" 1/4" & 3/4" end 3.24
CO120 3/8" X 3" X 1/16" (2) 1/4" 1/4" & 3/4" end 2.48

The coupons listed above can be made from a variety of materials (see Alloys list).

Cylindrical Coupons

corrosion coupons

P/N Size Thread Slot
ES200 1/4" X 2 1/2" 1/4"-20 X 3/8" 1/16"
ES201 1/4" X 2" 1/4"-20 X 3/8" 1/16"
ES202 1/4" X 3" 1/4"-20 X 3/8" 1/16"
ES204 1/4" X 1 1/2" 1/4"-20 X 3/8" 1/16"
ES209* 1/4" x 3" 1/4"-20 X 3/8"  

* ES209 has five 1/8" diameter scale holes.

Scale Coupons

Scale coupons (or deposition coupons) provide a qualitative measure of relative deposition rates in industrial water and manufacturing process systems.

corrosion coupons P/N CO115 - flat coupon
P/N ES209 - cylindrical coupon


Coupons can be furnished with a variety of finishes depending on your particular application. Some of the typical finishes available are defined below.

  • Mill - finish as produced from mill.
  • Glass Bead - blasted with fine glass beads to remove mill scale.
  • 120 Grit - fine finish using a 120 grit belt and commonly used in corrosion tests, such as pitting studies, where smooth surface finish is desired. Finishes up to 600 grit (extremely fine) can be provided by using belt sanders.
  • Double Disc Ground - extra fine finish using an abrasive disc that leaves minimal residue. Excellent for studies where surface finish is critical. Capable of producing 16-32 RMS finishes on common steels and 8 RMS on carbide steels.

Coupon Ordering

When placing your order for test coupons, please be ready to provide the sales person with information regarding the type of material you are testing, the size of the coupons you require, surface finish desired, and if applicable, mounting hole size and location.

Post-Exposure Coupon Analysis
Once coupons have been exposed in your system for the determined period of time, send them back to Metal Samples and let our technicians perform weight loss analysis to determine mils per year (MPY) corrosion rates. We are in strict adherence to ASTM-G1 specifications for cleaning and analyzing the coupons. When using this service, ensure that initial coupon weights, exposure dates, and locations are recorded for each sample. This information can be recorded on the front of our VCI coupon storage bags. Optional services include pit depth measurement and photos of the coupons before and after analysis.

corrosion coupon analysis

Coupon Storage Bags
Vapor corrosion inhibitor (VCI) bags are excellent for storage of ferrous and non-ferrous coupons. With VCI bags, coupons can be protected from corrosion for up to one year when stored under the proper environmental conditions. Pertinent test data, regarding pre- and post-coupon exposure, can be recorded in the appropriate spaces on the front of the bag. Ask for P/N BG5001 when ordering these bags.

corrosion coupon bags

Welded Coupons
Welded coupons are used to study the variance in corrosion rates between welded and non-welded metals.

Stressed Coupons
These coupons are used to monitor stress corrosion cracking which occurs when stress combines with a corrosive environment to attack a material.

Test Racks
We offer test racks for the mounting of coupons of various alloys to evaluate how corrosion would effect differing materials in your system.

Coupon Holders
We carry a variety of pipe plug coupon holders (for flat and round specimens), retractable coupon holders (hand insertable types for low pressure rating systems and packing gland types for ratings up to 1,500 psi.), and retrievable coupon holders (for up to 3,600 psi.).

Technical Information on Coupon Testing
This article provides general requirements for coupon tests, types of coupon tests, advantages of coupon testing, and other helpful information.

corrosion coupons
Bypass Piping Systems
Metal Samples provides bypass piping systems for on-line corrosion monitoring. More.

Alloys Available for Coupons
Alloys Listed by Trademark


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