5.3 WPS&PQR • QW-405 Position • QW-405.1 Position (+, N) The addition of other welding positions than those already qualified. See QW-120, QW-130, QW-203, and QW-303. • QW-405.2 Position ( φ, S ) A change from any position to the vertical position uphill progression. Vertical-uphill progression (e.g., 3G, 5G, or 6G position) qualifies for all positions. In uphill progression, a change from stringer bead to weave bead. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic material is solution annealed after welding. • QW-405.3 ↑↓ Vertical Welding ( φ, N ) A change from upward to downward, or from downward to upward, in the progression specified for any pass of a vertical weld, except that the cover or wash pass may be up or down. The root pass may also be run either up or down when the root pass is removed to sound weld metal in the preparation for welding the second side. • QW-406 Preheat • QW-406 Preheat - 예열(Preheating): 주요 목적은 Weld metal과 HAZ의 균열 방지 1) 냉각 속도를 늦춰 HAZ의 조직 경화 방지 -> Cold Crack 방지 2) 용접부 확산성 수소 방출 -> 수소 취성 및 저온 균열 방지 3) 용접부의 온도 구배를 낮추어 용접 변형과 잔류 응력 완화 # Preheating 관련 주요 Code ▪ ASME B31.3 Table 330.1.1 ▪ ASME SEC.VIII APP.R ▪ AWS D1.1 XI ▪ 기타 고객 Spec 규제 사항 확인 - 층간온도 (Interpass temperature): 다층 용접에서 모재가 데워져 있는 온도 일반적으로 최대 온도로 규제 1) CS: 강도 및 충격치 저하 2) SS: 크롬탄화물 발생 3) Duplex: Sigma 상 석출 [ API RP 582] - 층간 온도 유지 (Preheating Maintanc) : CS (25T 이상), Aolly Steel과 같이 최저 예열온도가 높은 경우 Torch, Electrical Heating pad 등 으로 온도 유지 Torch 사용 시 용접부에 불꽃이 직접적으로 닿지 않도록 주의. [ Torch] [Electrical Heating pad ] • QW-406.1 Decrease > 100°F (55°C) ( E ) A decrease of more than 100°F (55°C) in the preheat temperature qualified. The minimum temperature for welding shall be specified in the WPS. ex) PQ 시 100°C로 예열을 하였다면 WPS에는 최소 45°C까지 적용 가능 • QW-406.2 Preheat maint. (55°C) (φ, N ) A change in the maintenance or reduction of preheat upon completion of welding prior to any required postweld heat treatment • QW-406.3 Increase > 100°F (55°C) (IP) ( S ) An increase of more than 100°F (55°C) in the maximum interpass temperature recorded on the PQR. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic or P-No. 10H material is solution annealed after welding. ex) PQ 시 250°C가 최대 층간 온도 였다면 WPS 305°C까지 적용 가능 (Impact 적용) • QW-407 PWHT • QW-407 PWHT - 목적: 잔류 응력 완화, 용접부 및 구조물의 성능 개선 1) 경화된 열영향부를 연화시킨다. 특히 경도피크를 제거 2) 용접금속의 연성 증대 3) 용접금속 및 열영향부 파괴인성 향상 - 온도 및 유지 시간: CONSTRUCTION CODE(ASME B31.3, ASME SEC.VIII 등), 고객 SPEC 소재 업체의 경우 최종 열처리 반영 • QW-406.1 PWHT (φ, E ) A separate procedure qualification is required for each of the following: (a) For P-Numbers 1 through 6 and 9 through 15F materials, the following postweld heat treatment Conditions apply: (1) no PWHT (2) PWHT below the lower transformation temperature (3) PWHT above the upper transformation temperature (e.g., normalizing) (4) PWHT above the upper transformation temperature followed by heat treatment below the lower transformation temperature (e.g., normalizing or quenching followed by tempering) (5) PWHT between the upper and lower transformation temperatures (b) For all other materials, the following postweld heat treatment conditions apply: (1) no PWHT (2) PWHT within a specified temperature range • QW-408 Gas • QW-408 Gas ▪ Shielding gas: 용융 금속을 대리로부터 차단하여 산화 및 질화를 방지하는 역할 혼합가스를 사용하는 경우 안정된 Arc를 얻기 위함 가스의 성분 및 혼합 비율에 따라 용접성, 용입 깊이, GMAW, FCAW 경우 이행형태가 다르게 나타남 ▪ 대표적인 적용 Shielding gas - GTAW: Argon 99.997%, Ar + 2%N2 (Duplex) - FCAW: CO2 99.997%, Ar + 20% CO2 - GMAW: CO2 99.997%, Ar + 20% CO2, Ar + 2% O2 (Stainless steel) ▪ 적용 방법: 용접봉 제조사 Handbook 참조 ▪ 적용 Code: ASME Section II Part C SFA-5.32 • QW-408 Gas ▪ Backing gas: Single groove welding에서 Stainless Steel, Duplex 초층 용접시 산소와의 접촉으로 인한 산화 방지를 목적 으로 함 Argon 또는 Nitrogen을 주로 적용. Purging이라고도 부름 합격 불합격 AWS D18.2 The Sample Numbers refer to the amount of oxygen in the purging gas: No.1- 10ppm No.2 - 25ppm No.3 - 50ppm No.4 - 100ppm No.5 - 200ppm No.6 - 500ppm No. 7 - 1000ppm No.8 - 5000ppm No.9 -12500ppm No.10 -. 25000ppm Note: welds on type 304L SS showed no significant difference in heat tint colour from type 316L. • QW-408 Gas ▪ Trailing: 용착금속 응고시 발생하는 비드표면 산화 방지 목적으로 사용 산화에 민감한 Titanium에 주로 적용 ▪ Acceptable oxidations of welds in stainless steels [ NORSOK M-601 ANNEX. B] ▪ Acceptable oxidations of welds in stainless steels [ NORSOK M-601 ANNEX. B] • QW-408.1 ±Trailing or φ comp ( N ) The addition or deletion of trailing shielding gas and/or a change in its composition. • QW-408.2 Single, mixture or % ( φ, E ) A separate procedure qualification is required for each of the following: (a) a change from a single shielding gas to any other single shielding gas (b) a change from a single shielding gas to a mixture of shielding gasses, and vice versa (c) a change in the specified percentage composition of a shielding gas mixture (d) the addition or omission of shielding gas. The AWS classification of SFA-5.32 may be used to specify the shielding gas composition. • QW-408.3 Flow rate ( φ, N ) A change in the specified flow rate range of the shielding gas or mixture of gases. • QW-408.5 Backing flow (± or φ, N ) The addition or deletion of gas backing, a change in backing gas composition, or a change in the specified flow rate range of the backing gas. • QW-408.9 - Backing or φ comp ( E ) For groove welds in P-No. 41 through P-No. 49 and all welds of P-No. 10I, P-No. 10J, P-No. 10K, P-No. 51 through P-No. 53, and P-No. 61 through P-No. 62 metals, the deletion of backing gas or a change in the nominal composition of the backing gas from an inert gas to a mixture including non-inert gas(es). • QW-408.10 Shielding or trailing( φ, E ) For P-No. 10I, P-No. 10J, P-No. 10K, P-No. 51 through P-No. 53, and P-No. 61 through P-No. 62 metals, the deletion of trailing shielding gas, or a change in the nominal composition of the trailing gas from an inert gas to a mixture including non-inert gas(es), or a decrease of 10% or more in the trailing gas flow rate. • QW-409 Electrical Characteristics • QW-409.1 Heat input ( >, S) An increase in heat input, or an increase in volume of weld metal deposited per unit length of weld, over that qualified. The requirement for measuring the heat input or volume of deposited weld metal does not apply when the WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic or P-No. 10H material is solution annealed after welding. • QW-409.1 Heat input ( >, S) - Heat input (입열량): 용접시 용접봉 또는 전극에서 모재로 이동되는 에너지 - Heat input 공식: [ Heat input의 영향] 예민화 방지를 위한 용접 요건 용접 열영향 부위가 ASTM A262 방법 A 또는 E를 만족하지 못하는예민화 오스테나이트 스테인 리스강으로 되지 않도록 다음 사항을 신중히 관리한다. 가. 용접에 의한 입열량은 23.6 kJ/cm(60 kJ/in) 이하로 제한 나. 용접층간온도(interpass temperature)를 최대 176.7 ℃(350 ℉) 이내로 제한 다. 탄소함량을 0.065% 이하로 제한 • QW-409.2 Transfer mode (φ, E, GAMW & FCAW only) A change from spray arc, globular arc, or pulsating arc to short circuiting arc, or vice versa. [ Short circuiting] [ Spray] [ Globular] [ Pulsating] • QW-409.8 I & E Range (φ, N) A change in the range of amperage, or except for SMAW GTAW or waveform controlled welding, a change in the range of voltage. A change in the range of electrode wire feed speed may be used as an alternative to amperage. - 전류와 전압의 범위는 기계적 성질, Heat input, 작업성 까지 고려 하여 설정 용접봉 제조사의 권고사항을 참조 하되 엔지니어의 경험이 가장 중요함. [ GMAW 전류 영역 예시] • QW-409.12 Tungsten electrode (φ, N, GTAW Only) A change in type or size of tungsten electrode. - ASME SEC.III PART.C SFA-5.12 Tungsten and Oxide Dispersed Tungsten Electrodes for Arc Welding and Cutting • QW-410 Technique • QW-410.1 String / Weave (φ, N) For manual or semiautomatic welding, a change from the stringer bead technique to the weave bead technique, or vice versa. * Definition by ASME Section IX & AWS A 3.0 - Stringer Bead: weld bead formed without appreciable Weaving. - Weave Bead: weld bead formed using weaving. - Weaving: A welding technique in which the thermal source is oscillated transversely as it progresses along the weld path • QW-410.3 Orifice cup, or nozzle size (φ, N, GMAW, FCAW, GTAW) A change in the orifice, cup, or nozzle size. • QW-410.5 Method cleaning (φ, N) A change in the method of initial and interpass cleaning (brushing, grinding, etc.). [ Chipping] [ Brushing] [ Air Chipping] [ Brushing after Chipping] • QW-410.6 Method back gouge (φ, N) A change in the method of back gouging. [Arc air gouging] • Back gouging 순서 • QW-410.7 Oscillation (φ, N, SAW, GMAW, FCAW, GTAW) For the machine or automatic welding process, a change in width, frequency, or dwell time of oscillation technique. • QW-410.8 Tube-work distance (φ, N, SAW, GMAW, FCAW) A change in the contact tube to work distance. [Contact Tip to Work Distance] • QW-410.9 Multiple to single pass/side (φ, S & N) A change from multipass per side to single pass per side. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic or P-No. 10H material is solution annealed after welding. [Single Pass] [Multi Pass] • QW-410.10 Single to multi electrodes (φ, S & N) A change from single electrode to multiple electrode, or vice versa, for machine or automatic welding only. This variable does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic or P-No. 10H material is solution annealed after welding. • QW-410.15 Electrode spacing (φ, N) A change in the spacing of multiple electrodes or machine or automatic welding. [TANDEM SAW] • QW-410.11 Closed to out of chamber welding (φ, E, GTAW Only) A change from closed chamber to out-of chamber conventional torch welding in P-No. 51 through P-No. 53 metals, but not vice versa. (Titanium welding 적용) • QW-410.25 Manual or Automatic (φ, N) A change from manual or semiautomatic to machine or automatic welding and vice versa. • QW-410.26 Peening ( ±, N) The addition or deletion of peening. - 용접부를 특수 해머로 연속적으로 타격하여 표면층에 소성 변형을 주는 작업 용접부 잔류응력을 완화하는 효과가 있음. 표면에만 효과가 있으므로 두꺼운 경우 내부 응력 완화 효과 없으며 가공 경화로 경도 상승. • QW-410.65 Use of thermal process (φ, E) For vessels or parts of vessels constructed with P-No. 11A and P-No. 11B base metals, weld grooves for thickness less than 5⁄8 in. (16 mm) shall be prepared by thermal processes when such processes are to be employed during fabrication. This groove preparation shall also include back gouging, back grooving, or removal of unsound weld metal by thermal processes when these processes are to be employed during fabrication. QW300: Welding Performance Qualifications Table QW-355 Semiautomatic Gas Metal-Arc Welding (GMAW) [This Includes Flux-Co『ed Arc Welding (FCAW)] Essential Va『iables Para2raph QW-402 Joints QW-403 B ase Metals QW-404 Filler Metals Brief of Variables .4 - Backing .16 <P Pipe diameter .18 <P P-Number .15 <P F-Number .30 <P t Weld deposit t Limit (S. Cir. Arc.) .32 .1 + Position .3 <P iJ. Vertical welding QW-408 Gas .8 - Backing gas QW-409 Electrical .2 <P Transfer mode QW-405 Positions QW-302 TYPE OF TEST REQUIRED QW-302.2 Volumetric NOE. When the welder or welding operator is qualified by volumetric NDE, as per­ mitted in QW-304 for welders and QW-305 for welding operators, the minimum length of coupon(s) to be exam­ ined shall be 6 in. (150 mm) and shall include the entire weld circumference for pipe(s), except that for small dia­ meter pipe, multiple coupons of the same diameter pipe may be required, but the number need not exceed four consecutively made test coupons. The examination tech­ nique and acceptance criteria shall be in accordance with QW-191. QW-304 WELDERS Q1W-304.,,l Exa.mination. ·w·etds made in test coupons for, per'tOr'rnance qualification may b,e examined by visual , and mechanical examinations (QW,-302 11 1, QW' - 302,.4] or' b,y volumetr'i c ND1E (QW ' ,-302 11 2) for' the pr,ocess(es)i and mode 1o f ar'c transfer specified in QW-304, 11 Alter,natively, a minimum 6 in11, (150 mm) length 1o f the fir'st pr'oduction weld[s) made b,y a welder' using the pr 1ocess(es)i and/or' mode 1of ar'c tr'ansfer' specified in Q , W-3 04 may be exam·­ ined b,y volumetric ND1E lil
