Menu
Search
Filters
Close
Menu

Save 20% on select titles with code HIDDEN24 - Shop The Sale Now

Is 22 HRC the right threshold for TMCP large diameter pipes in severe sour environment?

Picture for Is 22 HRC the right threshold for TMCP large diameter pipes in severe sour environment?
Available for download

The manufacturing and field experience of high strength low alloy (HSLA) steel plates produced by Thermo-Mechanical Controlled Process (TMCP) are well defined in industry standards and literature. The TMCP method consists of a well-prescribed rolling pass schedule followed by accelerated cooling that leads to a fine-grain microstructure with the desired mechanical properties of the produced plates.
Quite recently, this TMCP process resulted in detrimental local variations with hidden hardness variations on pipe ID, so-called Local hard Zones (LHZ).

Product Number: 51323-18943-SG
Author: Hervé Marchebois, Christophe Mendibide, Bruce Cowe, Carole Dessolin
Publication Date: 2023
$0.00
$20.00
$20.00

Technical challenges and process improvements moved older generation Thermo-Mechanically Controlled Processing (TMCP) pipes from coarse microstructures and presence of non-metallic inclusions and/or mid-thickness segregation, to finer, homogenized microstructures and improved properties. Despite such an improvement, local hard zones (LHZ) have recently been experienced in the Oil & Gas industry on large diameter line pipes manufactured from TMCP plates, resulting in an in-service failure due to sulfide stress cracking (SSC).
After thorough investigations, it was confirmed the root cause of the failure was ascribed to microstructure heterogeneities while manufacturing the TMCP plates. Sub-surface lower bainite was identified as crack initiation areas, leading to the failures.
This paper deals with the results of a research program initiated to evaluate the SSC resistance of the actual microstructure associated to these hard zones. The first step was to analyze an industrial pipe section that experienced SSC in service. The microstructure observed was successfully reproduced in laboratory on specimen blanks using Gleeble thermo-mechanical cycles. Then, specimens were tested in different conditions of the Region 3 of the pH-PH2S severity diagram of NACE MR0175 / ISO 15156 to evaluate their cracking susceptibility. As a result, the maximum hardness limit of 22 HRC (248 HV) historically specified in standards shall not be considered as a safe limit if local hard zones are present at the surface of the material. Thus, the threshold should be decreased to 210 HV for safe use in Region 3 sour environments.

Technical challenges and process improvements moved older generation Thermo-Mechanically Controlled Processing (TMCP) pipes from coarse microstructures and presence of non-metallic inclusions and/or mid-thickness segregation, to finer, homogenized microstructures and improved properties. Despite such an improvement, local hard zones (LHZ) have recently been experienced in the Oil & Gas industry on large diameter line pipes manufactured from TMCP plates, resulting in an in-service failure due to sulfide stress cracking (SSC).
After thorough investigations, it was confirmed the root cause of the failure was ascribed to microstructure heterogeneities while manufacturing the TMCP plates. Sub-surface lower bainite was identified as crack initiation areas, leading to the failures.
This paper deals with the results of a research program initiated to evaluate the SSC resistance of the actual microstructure associated to these hard zones. The first step was to analyze an industrial pipe section that experienced SSC in service. The microstructure observed was successfully reproduced in laboratory on specimen blanks using Gleeble thermo-mechanical cycles. Then, specimens were tested in different conditions of the Region 3 of the pH-PH2S severity diagram of NACE MR0175 / ISO 15156 to evaluate their cracking susceptibility. As a result, the maximum hardness limit of 22 HRC (248 HV) historically specified in standards shall not be considered as a safe limit if local hard zones are present at the surface of the material. Thus, the threshold should be decreased to 210 HV for safe use in Region 3 sour environments.

Product tags
Also Purchased
Picture for Corrosion Behavior of Martensite-Based Stainless Steels in Chloride Solutions Saturated with CO2 Containing Impurity Gases
Available for download

Corrosion Behavior of Martensite-Based Stainless Steels in Chloride Solutions Saturated with CO2 Containing Impurity Gases

Product Number: 51323-18908-SG
Author: Yuichi Kamo, Kenichiro Eguchi, Hiroyuki Takai
Publication Date: 2023
$20.00

Carbon Capture and Storage (CCS) is a countermeasure for the global warming issue, and the number of CCS projects has increased. One type of CCS is Enhanced Oil Recovery (EOR), in which CO2 is injected into oil or natural gas reservoirs. Because formation water, which usually has a high concentration of chloride, exists at the bottom of these reservoirs, the injection tubing will suffer corrosion when the formation water flows back to the tubing. Stainless steels have been applied as tubing materials for Oil Country Tubular Goods (OCTG), and showed excellent corrosion resistance under high temperature and high CO2 pressure conditions. Martensite-based stainless steels bearing 13 mass% Cr to 17 mass% Cr are one of these tubing materials and are also expected to be used in CO2 injection tubing.
Picture for Contribution to the Understanding of Hydrogen Stress Cracking Initiation and Propagation in Nickel Based Alloys
Available for download

Contribution to the Understanding of Hydrogen Stress Cracking Initiation and Propagation in Nickel Based Alloys

Product Number: 51323-18873-SG
Author: Bruce Cowe, Flavien Vucko, Hervé Marchebois, Laurent Ponson
Publication Date: 2023
$20.00

This paper presents work in follow-up to the previous study. It is focused on UNS1 N07718, UNS N09925, UNS N07725 and UNS N09946. A series of incremental step load tests of compact tensile specimens were conducted to measure the fracture toughness during testing and cracking was monitored by the Electric Crack Growth Monitoring technique. A new engineering technique, referred to as statistical fractography, was used to investigate the fracture surface morphology and extract from it the fracture properties of the alloys.
Picture for Effective Corrosion Inhibitor Formulation for Carbon Steel in Downhole Sweet Gas Wells
Available for download

Effective Corrosion Inhibitor Formulation for Carbon Steel in Downhole Sweet Gas Wells

Product Number: 51323-19009-SG
Author: Ime Bassey Obot, Ahmad A. Sorour, Tao Chen, Qiwei Wang
Publication Date: 2023
$20.00

Corrosion of the internal surfaces of pipelines is one of the serious issues facing the oil and gas industry. Produced oil and gas always contain some water mixed with brines and contain varying amounts of carbon dioxide (sweet gas), hydrogen sulfide (sour gas) and organic acids1. All of these can affect the integrity of the low-carbon steel pipes used in the construction of downhole gas wells. CO2 gas, along with the high salt content of production water, causes serious corrosion on the internal walls of corrosion resistance alloys (CRAs) and steel pipelines used in downhole gas wells.
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support