Category: WELDING

WELDING8 Comments

WPS Understanding – Part 1

Thanh ( QC ) Nguyen Le

Dear all, This topic we just introduce you How to read, understand & use a WPS ( welding procedure specification ). Example WPS for refer Some definitions you need understand before start it. What is WPS? is a written document that provides direction to the welder or welding operator for making production welds in accordance with code requirements. The completed WPS shall describe all the essential , non essential and when required supplementary essential variables for each welding process used in the WPS.   2. What is PQR ( procedure qualify record )? is a record of the weld data … Continue reading WPS Understanding – Part 1

CSWIP 3.0/3.1/3.2, WELDINGLeave a comment

CSWIP 3.1 CODES, WPS, WELD REPAIR

Amarine Antonio

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 3.0/3.1/3.2, WELDING1 Comment

CSWIP 3.1 WELDABILITY

Amarine Antonio

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 3.0/3.1/3.2, WELDING1 Comment

CSWIP 3.1 DT & NDT

Amarine Antonio

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 3.0/3.1/3.2, WELDING1 Comment

CSWIP 3.1 RESIDUAL STRESSES AND DISTORTION

Amarine Antonio

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 3.0/3.1/3.2, WELDING1 Comment

CSWIP 3.1 WELDING PROCESSES

Amarine Antonio

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 3.0/3.1/3.2, WELDING1 Comment

CSWIP 3.1 WELDING CONSUMABLES

Amarine Antonio

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