THE RESISTANCE TO FAILURE OR CRACK
USED TO MAKE STEEL SOFT & DUCTILE BY HEATING A METAL TO TEMPERATURE ABOVE CRITICAL TEMPERATURE FOR A PERIOD FOLLOWED BY COOLING @ SUITABLE RATE ACCORDING TO THE PURPOSE
STEEL WITH DISTINCTIVE PROPERTIES MINIMUM COMPONENT (SILICON 0.6, COPPER 0.6, MANGANESE 1.65)
Martensitic transformation, more commonly known as quenching and tempering, is a hardening mechanism specific for steel. The steel must be heated to a temperature where the iron phase changes from ferrite into austenite, i.e. changes crystal structure from BCC (body-centered cubic) to FCC (face-centered cubic) then “quenched” (rapidly cooled), often in oil or water
The piping material selection process is a critical step in the design of any piping system . The goal is to choose materials that ensure the safe, reliable, and cost-effective transport of fluids while withstanding the operating conditions and environmental factors . Here’s a detailed explanation of the process:
- Define Service Requirements:
- Fluid Type: Identify the fluid(s) to be conveyed, including their chemical composition and physical properties .
- Operating Conditions: Determine the operating temperature, pressure, and flow rate ranges .
- Codes and Standards: Identify applicable codes, standards, and regulations (e.g., ASME B31.3, B31.1, API standards) .
- Determine Material Properties Required:
- Corrosion Resistance: Select materials resistant to internal and external corrosion based on the fluid’s corrosivity and the external environment .
- Strength and Ductility: Ensure materials have adequate tensile strength, yield strength, and ductility to withstand operating pressures and mechanical stresses .
- Temperature Resistance: Select materials that maintain their strength and integrity at the operating temperature range, considering creep, embrittlement, and thermal expansion .
- Weldability: If welding is required, choose materials with good weldability to ensure sound joints .
- Erosion Resistance: For abrasive fluids or high velocities, select materials with good erosion resistance .
- Thermal Conductivity: Consider thermal conductivity for heat transfer applications or to prevent overheating or freezing .
- Fatigue Resistance: For systems with cyclic loading, select materials with good fatigue resistance .
- Evaluate Material Options:
- Carbon Steel: A common and cost-effective material for many applications, but susceptible to corrosion in some environments .
- Stainless Steel: Offers excellent corrosion resistance and high-temperature strength, suitable for corrosive fluids and high-temperature services .
- Alloy Steel: Used for high-temperature, high-pressure, or specialized applications requiring enhanced strength, creep resistance, or corrosion resistance .
- Non-Ferrous Metals: Copper, aluminum, and nickel alloys are used for specific applications based on their unique properties (e.g., high thermal conductivity, corrosion resistance) .
- Plastics: PVC, CPVC, PP, PVDF, and other plastics are used for corrosive fluids, low-pressure applications, and deionized water systems .
- Consider Fabrication and Installation Requirements:
- Welding: Select materials that can be easily welded using standard welding procedures .
- Formability: Consider the material’s formability for bending, threading, and other fabrication processes .
- Availability: Ensure that the selected materials are readily available in the required sizes and forms .
- Assess Cost:
- Material Cost: Compare the cost of different materials, considering both the initial cost and the long-term cost of maintenance and replacement .
- Fabrication Cost: Consider the cost of welding, forming, and other fabrication processes .
- Installation Cost: Evaluate the ease of installation and any special requirements (e.g., specialized welding procedures, supports) .
- Check Industry Standards and Regulations:
- ASME B31.3: Specifies material requirements for process piping .
- ASME B31.1: Specifies material requirements for power piping .
- API Standards: Provide guidelines for material selection in the petroleum and natural gas industries .
- Local Regulations: Ensure compliance with local building codes and environmental regulations .
- Make Final Selection:
- Document the Selection Process: Document the rationale for selecting the chosen materials, including the factors considered and the alternatives evaluated .
By following these steps, engineers can select the most appropriate piping materials for a given application, ensuring the safety, reliability, and longevity of the piping system .
I. Purpose
- To ensure that all piping materials received at the job site conform to the specified requirements of the project and ASME B31.3
- To establish a system for verifying material identity, quality, and documentation
- To prevent the use of non-conforming materials in the piping system
II. Scope
This procedure applies to all piping materials, including pipes, fittings, flanges, valves, gaskets, bolts, and other components used in the construction of piping systems
III. References
- ASME B31.3, Process Piping
- ASME Section II, Materials
- Project Piping Material Specification
- Approved Piping Drawings and Material Take-Offs (MTOs)
- Purchase Orders
- ASTM Standards (as applicable to specific materials)
- Company Quality Control Manual
IV. Responsibilities
- Procurement Department: Responsible for ensuring that purchase orders accurately reflect the project’s material requirements
- Receiving Inspector: Responsible for performing the receiving inspection in accordance with this procedure
- Quality Control (QC) Engineer: Responsible for overseeing the receiving inspection process and resolving any non-conformance issues
- Material Controller: Responsible for maintaining material traceability and storage
V. Procedure
A. Pre-Receiving Activities
- 1. Review Documentation: Before material arrives, the Receiving Inspector shall review the Purchase Order, Material Requisition, Piping Material Specification, and approved drawings to understand the material
- 2. Prepare Inspection Area: Ensure a designated receiving area is available with adequate lighting, measuring tools, and access to relevant specifications
- 3. Obtain Approved Vendor List: Verify that the material supplier is an approved vendor per the project’s quality control requirements.
B. Receiving Inspection Steps
1. Visual Inspection:
- Verify Packing List: Check the packing list against the purchase order to confirm the correct quantity and description of materials received
- Inspect for Damage: Carefully examine all materials for any signs of damage during shipping, such as dents, bends, corrosion, or broken packaging.
- Document any damage on the receiving report and notify the supplier
- Check for Proper Marking: Verify that each item is clearly and legibly marked with the correct material grade, size, schedule, and heat number.
- Markings should comply with applicable standards (e.g., ASME, ASTM)
2. Material Verification:
- Review Material Test Reports (MTRs): Obtain and review the MTRs (also known as Certified Material Test Reports or CMTRs) for each material lot
- Compare MTRs to Specifications: Verify that the chemical composition, mechanical properties (tensile strength, yield strength, elongation), and heat treatment listed on the MTRs meet the requirements of the applicable material specification (e.g., ASTM A106 Grade B, ASTM A105) and the project piping material specification
- Verify Traceability: Ensure that the heat number on the MTR matches the heat number marked on the material
- This confirms traceability of the material back to its origin
- Positive Material Identification (PMI): For critical applications or materials susceptible to mix-ups (e.g., alloy steels), perform PMI using a portable spectrometer to verify the material’s chemical Document PMI results
3. Dimensional Verification:
- Check Dimensions: Using calibrated measuring tools (e.g., calipers, tape measure), verify that the dimensions of the received materials (pipe diameter, wall thickness, flange dimensions, fitting dimensions) conform to the specified standards and the project drawings
- Verify Wall Thickness: Use ultrasonic thickness testing to verify the wall thickness of pipes and fittings, especially for corrosion-resistant alloys.
4. Specific Component Checks:
- Pipes: Check for straightness, ovality, and surface defects
- Fittings: Verify the angle, radius, and end preparation (e.g., bevel angle for welding
- Flanges: Check flange face finish, bolt hole alignment, and dimensions
- Valves: Verify valve type, pressure rating, end connections, and operator type. Check for smooth valve operation
- Bolting: Verify bolt diameter, length, material grade, and thread
- Gaskets: Check gasket type, size, and material compatibility with the intended
5. Documentation:
- Complete Receiving Inspection Report: Document all inspection results on a receiving inspection report, including the purchase order number, material description, quantity inspected, inspection date, inspector’s name, and any discrepancies or non-conformances
- Attach MTRs: Attach copies of the MTRs to the receiving inspection
- Maintain Records: Maintain a file of all receiving inspection reports, MTRs, and related documentation for future
C. Non-Conformance Handling
- 1. Identify Non-Conformances: Any material that does not meet the specified requirements shall be identified as non-conforming
- 2. Segregation: Segregate non-conforming materials from conforming materials to prevent accidental use
- 3. Notification: Notify the QC Engineer and Procurement Department of the non-conformance
- 4. Disposition: The QC Engineer will determine the appropriate disposition of the non-conforming material, which may include:
- Return to Supplier: Return the material to the supplier for replacement or credit
- Repair: Repair the material, if possible, and re-inspect to verify conformance
- Use-as-is: Accept the material “as-is” with a deviation, if it is determined that the non-conformance does not affect the safety or functionality of the piping system. This requires approval from the Engineering Department and the client, if
- 5. Documentation: Document the non-conformance and the resolution on a Non-Conformance Report (NCR)
D. Material Storage and Handling
- Proper Storage: Store materials in a clean, dry, and secure area to prevent damage or deterioration
- Material Identification: Maintain material identification throughout storage and handling
- Handling Procedures: Use proper lifting and handling equipment to prevent damage to materials
- Inventory Control: Implement an inventory control system to track the location and status of all piping materials
VI. Acceptance Criteria
- Materials are accepted if they meet all the requirements of this procedure, the applicable material specifications, and the project piping material
- All documentation is complete and accurate
- There are no unresolved non-conformances
VII. Training
All personnel involved in the receiving inspection process shall be trained on this procedure and the relevant material specifications
VIII. Records
- Receiving Inspection Reports
- Material Test Reports (MTRs)
- Non-Conformance Reports (NCRs)
- Purchase Orders
- Material Requisitions
- Calibration Records for Measuring Equipment
- PMI Reports
This comprehensive procedure ensures that all piping materials are thoroughly inspected upon arrival at the job site, minimizing the risk of using non-conforming materials and ensuring the integrity of the piping system
Remember to adapt this procedure to your specific project requirements and company standards.
Stainless steels may be classified by their crystalline structure into four main types: austenitic, ferritic, martensitic and duplex
Difference between 304 and 316 stainless steel?
The simple answer is 304 contains 18% chromium and 8% nickel while 316 contains 16% chromium, 10% nickel and 2% molybdenum. The molybdenum is added to help resist corrosion to chlorides (like sea water and deicing salts)
| ASTM Group 2-1.1 Materials | ASTM Group 2-2.3 Materials | |||||||
| Nominal | Forgings | Castings | Plates | Nominal | Forgings | Castings | Plates | |
| Designation | Designation | |||||||
| C-Si | A105(1) | A216 | A515 | 16Cr 12Ni 2Mo | A182 | … | A240 | |
| Gr.WCB(1) | Gr.70(1) | Gr.F316L | Gr.316L | |||||
| C Mn Si | A350 | … | A516 | 18Cr 13Ni 3Mo | A182 | … | … | |
| Gr.LF2(1) | Gr.70(1),(2) | Gr.F317L | ||||||
| C Mn Si V | A350 | … | A537 | 18Cr 8Ni | A182 | … | A240 | |
| Gr.LF6 Cl 1(3) | Cl.1(4) | Gr.F304L(1) | Gr.304L(1) | |||||
| 3.1/2Ni | A350 | … | … | |||||
| Gr.LF3 | ||||||||
| Notes: | Note: | |||||||
| (1) Do not use over 425°C. | ||||||||
| (1) Upon prolonged exposure to temperatures above 425°C, the carbide phase of steel may be converted to graphite. Permissible but not recommended for prolonged use above 425°C. | ||||||||
| (2) Do not use over 455°C. | ||||||||
| (3) Do not use over 260°C. | ||||||||
| (4) Do not use over 370°C. | ||||||||
Zinc, aluminum and magnesium are more electronegative than steel they are increasingly able to supply electrons to the more electropositive steel when in electrical contact in water,
Mill Test Report or MTR is documentation from a testing facility that usually shows the chemical makeup and physical strength/properties of materials required to meet certain ASME and ASTM grades
Phosphorus has four major effects on iron: increased hardness and strength, lower solidus temperature, increased fluidity, and cold shortness