CSWIP 3.1 CODES, WPS, WELD REPAIR
Key notes: Definitions: STANDARD: Document established by concensus/ agreement and approved by recognised body (class/third parties ) Ex: Yard standard/ Subcon standard approved by Owner & Class, or JIS/AISI HARMONISED STANDARD: Document established for interchangability of products, processes, services Ex: ISO/IACS/IEC CODE OF PRACTICE, or Set of Manufacture rule Procedure for design/manufacture/installation/utilization. CAN BE A STANDARD, PART OF STANDARD OR INDEPENDENT OF A STANDARD Ex: ASTM/ ASME/ ANSI/ DIN/ JIS REGULATION: Ligislative rules adopted by authority Ex: IMO/ILO/MARPOL/OCIFM SPECIFICATION: Meanningful data supporting stating needs & expectation with obligatory Ex: Contract specification/ project specification PROCEDURES: Established specified way/process activites following Spec/Code/Standard … Continue reading CSWIP 3.1 CODES, WPS, WELD REPAIR
CSWIP 3.1 HEAT TREATMENT
Key notes: PWHT-STRESS RELIEF (No phase transformed) For C-S: ~ 350*C For S-S: ~ 500*C PWHT-HYDROGEN RELEASE Temp ~ 250*C/inch/hour (max 3 hours) PWHT CONTROL: TEMP WORKS FOR STEEL: Continue reading CSWIP 3.1 HEAT TREATMENT
CSWIP 3.1 WELDABILITY
Key notes: General: Weldability depend on Carbon and alloy elements Poor weldability mean –> the occurrence of cracking Alloying elements: Carbon Most effect to the Hardness Hardness is invert proportion Ductility %C typical <~ 0.25-0.3% %CE or CVE ~ 0.4-0.5% Manganese De-sulfure –> reduce rick of Hot cracks (Solidification Crack) C-S (<0.8% Mn) vs C-Mn-S (<1.6% Mn) Molybdenum For Creep resistance (at High temp operation) HIC Higher susceptible in Alloy C-S (crack in weld) than C-S (crack in HAZ) Chevron (arrow) crack most occurred in SAW HIC never happen in Ni/Cu alloy (they can’t be harden by heat) … Continue reading CSWIP 3.1 WELDABILITY
CSWIP 3.1 DT & NDT
Key notes: General: Fillet weld fracture and Butt weld nick-break tests are not used for WPS (only for WPQR) CTOD impact test is used for Special concern in specification, not WPS Hardness test: (Brinell-BHN/Vicker-HV/Rockwell-Rc) Hardest region Impact test: Izod vs Charpy Visual assessment Tensile test: Proof stress Rp 0.2 – used for un-identified Y.S material (aluminium) Measuring the “overall strength of weld joint” –> TRANSVERSE T.S TEST All weld metal T.S test –> For Electrode Manufacture only! STRA Test: Macro/Micro Examination: This is Quantity Test Bend Test: This test CAN evaluate the Fusion and Ductility T < 12mm … Continue reading CSWIP 3.1 DT & NDT
CSWIP 3.1 RESIDUAL STRESSES AND DISTORTION
Key notes: How many types (typical) ? Transverse Short-transverse (Non-uniform contraction through thickness) Longitudinal Thermal expansion is the greatest affecting factor (Alu, SS) “Yield strength – Y.S direct proportion with Residual Stress BUT Y.S is inverse proportion with Distortion (Because of elastic state/thermal expansion)“. Neutral axis welding for distortion prevention Strong-backing method used for Thicker plate only. Back step/Skip welding method used for Thinner plate Continue reading CSWIP 3.1 RESIDUAL STRESSES AND DISTORTION
CSWIP 3.1 WELDING DEFECTS
Key notes: Undercut Excessive reinforcement protection The most serious defect – Surface breaking (Lack of Interun fusion on cap) Burn though Arc strike REPAIRING METHOD LOP/LOF Continue reading CSWIP 3.1 WELDING DEFECTS
CSWIP 3.1 WELDING PROCESSES
Key notes: General: Typical H.I from 1 – 3.5 kJ/mm Plastic state welding or Non-fusion welding CC or CV Polarity and Penetration ability Operation Factor vs Duty Cycle Affection of Torch Angle MMA: Typical OCV : 50-90V and Operation range : 20-40V Arc blow because of Magnetic force (DC) –> Prevent by using AC Run Out Length (ROL) –> For measuring the welding Speed TIG: Typical OCV : 50-90V and Operation range : 20-40V Filler rod – consumables vs Electrode – nonconsumable HF – high frequency Arc starting can Damage the equipments AC used for Al and Mg (Because of Best Cleaning … Continue reading CSWIP 3.1 WELDING PROCESSES
CSWIP 3.1 WELDING CONSUMABLES
Key note: Storage Condition Dew point of Consumable Gas: – 60 Deg Filler material must be stored in an area with controlled temperature and humidity. MMA Consumables Core wire made by Rimming steel Weld properties controlled by covering Flux Silicon (De-oxidizer) added to Flux to avoid the Porosity inhibited by rimming steel Flux types comparison: Flux types identification: Impact test energy as per EN ISO 2560: Tensile strength or Yield Strength SS – ELECTRODE SMALLER THAN CS ELECTRODE BECAUSE OF LOWER ELECTRIC CONDUCTIVITY. TIG Consumables EB INSERT (SEE TERMS AND DEFINITIONS) Nitrogen will not be used for Ni,Ni-alloys and Mild … Continue reading CSWIP 3.1 WELDING CONSUMABLES
CSWIP 3.1 WELDING SYMBOLS
Key notes: Identification – – – – – – -(ISO)- – – – – – – / Reference lines Identification line (ISO) can be omitted in asymmetric joint Staggering symbol AWS vs ISO Peripheral (ISO) or Well all around (AWS) Partial penetration weld, “S” “z”– Leg size or “a” – Throat thickness Process identification between AWS and ISO Continue reading CSWIP 3.1 WELDING SYMBOLS
AMARINE 