Inside Exploration Technologies

GR specializes in performing heat treatment for the steel and metal fabrication industries including the construction of pressure vessels, pressure piping, storage tanks, buildings, bridges, offshore platforms, power plants, oil and gas refineries, and petrochemical plants.

There is often a mandatory requirement for heat treatment due to compliance with welding codes and specifications on certain materials including but not limited to carbon steels, stainless /high alloy steels, and work-hardened steels. There may also be heat treatment requirements based on the wall thickness of the parts being welded together.

Heat Treatment reduces or redistributes the residual stress introduced by the welding process with a technique that involves heating, soaking, and cooling the weldment/machined surface to controlled temperatures.

Pre-Heating

Thermal stresses are set up as a molten weld cools. Cracking can occur during and after welding. Pre-heating reduces the temperature differentials between the weld metal and the parent metal, thus minimizing the tendency to crack.

Post Weld Heat Treatment (PWHT)

PWHT is carried out by an electrical resistant method or by (furnace firing or internal firing) with high-velocity fuel burners. There are three main benefits, stress relaxation, tempering, and hydrogen removal. The first two benefits are generally the reason for the heating operation, with hydrogen removal being considered as a bonus.

Normalizing

Normalizing / Annealing heat treatment is to improve the mechanical properties of steel, tensile strength, and impact value, leading to better resistance to brittle fracture. For instance, with mild steel, the temperature would be approximately 900ºC (1650F) which is 50ºC above the upper critical point.

Solution Heat Treatment

Certain types of austenitic stainless steel undergo structural changes in the range of 500º to 800ºC which are detrimental to their corrosion resistance properties. Weld decay occurs. One method of obtaining immunity from decay is by raising the material to 1000 – 1150ºC followed by rapid cooling.

Refractory Dry Out

All types of furnaces have a kind of refractory insulating installed in them and this needs to be dried out the method in heating the surface gradually until it reaches the recommended manufacturer procedure.

Phased array technology is an ultrasonic method with the capability of setting beam parameters such as angle, focal distance, and focal point size through computer-controlled excitation. The computers allow individual excitation of multi-element probes and allow Inspection of parts with variable-angle beams. This maximizes the detection of defects regardless of their orientation while optimizing signal-to-noise ratio.

Phased array is a typical volumetric inspection method that has a wide range of applications including weld inspection, crack detection, and corrosion monitoring. Phased Array approach for inspection of welds has been accepted by ASME instead of radiography, ASME CC 181, and CC 2235-9.

Advantages

• Excellent repeatability
• Full stored data for records
• High Quality Inspections
• Rapid Inspection & Results
• No disruption to work or operation of equipment
• No radiation or any other safety issues
• Considering overall, much cheaper and faster than RT.

Applications

• Phased Array Corrosion Mapping
• Phased Array Flange Inspection
• Phased Array on Pipeline
• Phased Array on small bore piping

Automated Ultrasonic Testing (AUT) uses a multi-channel digital ultrasonic system with a motor-driven scanner to perform an on-stream inspection on a wide range of equipment. In AUT, normal Pulse-Echo is used while performing Corrosion Mapping, hydrogen cracking, and other related cracking, ToFD is used for heavy wall reactors, vessels, and piping, and Phased Array for complex geometries (nozzles, branch connections, flange faces, etc…)

Exploiting the multi-channel arrangement, two or more techniques can be combined in one scan suiting the client's requirement which increases the overall output and efficiency of the system.

Advantages

• Optimizes the inspection spend.
• Ability to document and present visually the defect size.
• High repeatability allows continuous monitoring of critical flaw growth.
• Collect and image data in real-time and to store this data in electronic format.
• Minimizes costly internal entry, and inspection performed while in service.
• “On-line” inspection promotes efficient planning.
• Comply with regulatory and industry standards and specifications.
• Assists RBI, FFS, and RLA programs.

Applications

• In-service scanning of vessels, tank walls, towers, drums, steel plates, in-line inspection validations, pipelines, and numerous other applications.
• Gives maximum production and efficiency with a multi-channel digital meter, motorized scanning system, and multiple transducers.
• Single pulse echo transducers and/or multiple angle pulse echo transducer configurations enable location and identification of nearly any type of damage mechanism such as corrosion-erosion, hydrogen induced cracking, stepwise cracking, stress corrosion cracking, laminations, etc.

ToFD uses two longitudinal wave (L-Wave) angle beam transducers arranged symmetrically opposite to each other. One probe acts as a transmitter of ultrasonic energy while the other probe as receiver, in a pitch-and-catch mode. A single-axis scan with an encoder recording the position of the weld enables the display of digital images in real-time. ToFD detects and records signals diffracted from defect tips for both detection and sizing. The TOFD data is displayed in a grayscale B-scan view.

ToFD approach for inspection of welds has been accepted by ASME instead of radiography, ASME CC 181, and CC 2235-9. ToFD has an accuracy for measurement of remaining wall loss is estimated typically as ± 0.75 mm. The accuracy of measurement of change of wa II thickness within a single scan is estimated at ± 0.50 mm.

Advantages

• Utilizing diffracted signals, detectability does not depend upon defect orientation.
• The setup is independent of the weld configuration.
• No difficulty in detecting planar defects or cracks in any orientation.
• Defect height can be accurately measured.
• Inspection results are readily available
• High speed and high repeatability in performing inspection
• More economical compared to radiography for thicknesses above 25 mm
• Inspection can be performed at the range of 200 °C.
• High portability and versatility allow it to be used in difficult-to-access areas via rope access.

Applications

• New and existing welds with a minimum wall thickness of 7 mm and above.
• For service-induced defects & structural damage
• Stress/ chemically assisted micro-cracking – SCC, LTHA
• Components with high wall thickness
• Corrosion/ erosion profiling
• Pressure systems, vessels, tanks, spheres, pipelines, etc.

Guided Wave Ultrasonic method, also known as Long Range UT is used to inspect 100% of a pipe segment from one location. Its primary application is within the Oil and Gas Refining, Petrochemical, Storage, Offshore, and Pipeline Transportation industries used to inspect difficult-to-access piping systems.

Guided waves are induced into the pipe body and propagated along the pipe segment being inspected. Upon identifying an anomaly or pipe feature, the mode-converted flexural waves reflect the original tool position. The time-of-flight is used to calculate the distance from the tool, while the amplitude is related to the cross-sectional area. Then the circumferential extent determined by the focused beams provides the information to determine the significance of the defect.

Advantages

Unlike traditional inspection methods that provide value, GUL promotes condition-based inspection programs aimed at supporting mechanical integrity and preventive maintenance programs. For the same reason, many have chosen to inspect their piping systems using GUL Inspection. The benefits include:

• Large sections of piping can be inspected rapidly and safely often with no scaffolding.
• Minimal insulation removal for Corrosion Under Insulation (CUI) inspections.
• Localized damage can be pinpointed and characterized according to length and depth.
• An excellent tool for cased crossings and unpiggable pipe.
• Point of contact corrosion can be found without moving the pipe, avoiding potential leaks.

The GUL rings and its laptop is extremely portable, which enables the Global Remote crew to inspect the most difficult-to-access areas through rope access very easily, thereby considerably reducing inspection time and cost.

What all can be inspected?

• Insulated Pipe
• Offshore Pipeline Risers
• Cased Road or Railway Crossings
• Loading Lines and associated Pipework
• Tank Dyke Pipeline Crossings
• Above Ground or Buried Flow Lines
• River or Bridge Pipeline Crossings