In-Situ Nondestructive Positive Material Identification Testing For Determining Carbon Steel Pipeline Material Properties

TDW has developed and validated a non-destructive Positive Material Identification test method used to identify unknown carbon steel line pipe in the oil and gas industries to determine material grade based on the American Petroleum Institute 5L Specification. This process identifies both Yield and Tensile strength values along with chemical analysis and carbon equivalence. When these PMI methods are used for material evaluation, within the scope, limitations and guidelines of the validated PMI procedures, accuracy tolerances have been validated as follows:  Ultimate Yield Strength (UYS) +/-10% with a 95% Confidence Level  Ultimate Tensile Strength (UTS) +/-10% with a 95% Confidence Level  Carbon percentage (C) +/-25% with an 85% Confidence Level  Manganese percentage (Mn) +/-20% with a 90% Confidence Level Our process requires exposing a minimum three feet section of pipe and coating removal for 360 degrees around the pipe. Prior to this development, customers generally had to rely on destructive test methods to determine these values which may have included a line shut-down, destructive removal of a test coupon and off-site laboratory testing. This process was time consuming, expensive and labor intensive (often requiring a line by-pass). This PMI procedure is truly non-destructive and is performed in-situ, providing material property assessment without pressure reductions, while the line remains in service.

1. API-5L Specification for Line Pipe 2. ASTM-A751-14 Standard Test Methods. Practices, and Terminology for Chemical Analysis of Steel Products 3. ASTM E415-08 Standard Test Method for Atomic Emissions Vacuum Spectrometric Analysis of Carbon and Low-Alloy Steel 4. ASTM E2546-07 Standard Practice for Instrumented Indentation Testing
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