This standard establishes guidelines to prevent most forms of environmental cracking of weldments in carbon steel refinery equipment, including pressure vessels, heat exchangers, piping, valve bodies, and pump and compressor cases. Weldments are defined to include the weld deposit, base metal HAZ, and adjacent base metal zones subject to residual stresses from welding. It defines standard practices for producing weldments in P-No. 1 steels resistant to environmental cracking in corrosive petroleum refining environments. This standard is maintained by Task Group 326.
STABILIZATION NOTICE: This document has been declared “Stabilized” by AMPP Standards Committee (SC) 03 and will no longer be subjected to periodic reviews for currency.
This specification covers a coal-tar emulsion coating to be used as a protective weather coat for hot- or cold-applied bituminous coatings on steel structures. It may also be used over suitable primers as a protective coating for aboveground steel structures subjected to atmospheric exposure and the deleterious effects of oxidation and ultraviolet radiation.
Stabilized austenitic stainless steel (SS) grade 347 is used extensively in high-temperature processes in the petroleum refining industry, while duplex SS (DSS) grade 2205 is a relatively newer material in the industry. Though these grades of SSs perform well in refinery process streams, there are incidents of failure of process equipment attributable to stress corrosion cracking (SCC). The paper deals with a study on the cracking susceptibility of SS grade 347 and DSS grade 2205 in refinery simulated process environments containing hydrogen sulfide and chloride. The paper also reports the electrochemical behavior of these SSs in the medium containing hydrogen sulfide and chloride. The electrochemical behavior of the alloys was assessed by cyclic polarization experiments. Slow strain rate test (SSRT) was used to evaluate the susceptibility of the alloys to SCC. The cyclic polarization studies indicate that the H2S – chloride synergism had a pronounced effect on the localized corrosion susceptibility of 347 SS, while the effect was marginal on the alloy DSS 2205. The SCC susceptibility of 347 SS and DSS 2205 is strongly influenced by hydrogen sulfide-chloride synergism. Initiation of corrosion pits and the sulfidation of active pits due to the synergism were the important steps in the initiation of SCC.
The purpose of this NACE International technical report is to provide basic information regarding the mechanisms involved with cathodic protection (CP) shielding for external coatings applied to carbon steel pipelines, and the manner in which the breakdown of coating systems may or may not contribute to CP shielding. It is intended to be a basic reference from which the tendency of a coating system to fail and shield CP may be understood on a conceptual basis. Non-corrosion-related pipeline protection systems, including concrete weight coating, polyethylene encasement, insulation, and mechanical pipeline protection systems, are outside the scope of this report. End users of this report may include pipeline designers, corrosion engineers, integrity management specialists, regulators, CP service providers, coating suppliers, coating service providers, equipment suppliers, and pipeline/facility owners.
Revised in 2020! Assessment of corrosion in the field is complex because of the variety of applications, process conditions, and fluid phases that exist in industrial plants where corrosion occurs. A wide range of direct and indirect measurement techniques is available, but each technique has its strengths and weaknesses. In some applications, certain techniques cannot be used. Some techniques can be used online, while others are used off-line. Commonly, more than one technique is used so the weaknesses of one are compensated for by the strengths of another. In other cases, a combination of different techniques can be synergistic, such as process sampling along with detection of corrosion upset.
The purpose of this technical committee report is to analyze the various techniques with respect to their benefits and limitations across the broad spectrum of industries in which they are used.
This revision incorporates Guided Wave Monitoring (GWM), On-Line Gas Chromatography (GC), and Acoustic Solid Detection (ASD) techniques and updates references to NACE standards.