KR0122116B1 - Corrosion testing method for grain boundary of welding stainless steel - Google Patents

Corrosion testing method for grain boundary of welding stainless steel

Info

Publication number
KR0122116B1
KR0122116B1 KR1019940039361A KR19940039361A KR0122116B1 KR 0122116 B1 KR0122116 B1 KR 0122116B1 KR 1019940039361 A KR1019940039361 A KR 1019940039361A KR 19940039361 A KR19940039361 A KR 19940039361A KR 0122116 B1 KR0122116 B1 KR 0122116B1
Authority
KR
South Korea
Prior art keywords
test piece
corrosion
test
stainless steel
grain boundary
Prior art date
Application number
KR1019940039361A
Other languages
Korean (ko)
Other versions
KR960021354A (en
Inventor
유호천
Original Assignee
김만제
포항종합제철주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 김만제, 포항종합제철주식회사 filed Critical 김만제
Priority to KR1019940039361A priority Critical patent/KR0122116B1/en
Publication of KR960021354A publication Critical patent/KR960021354A/en
Application granted granted Critical
Publication of KR0122116B1 publication Critical patent/KR0122116B1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K31/00—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups
    • B23K31/12—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups relating to investigating the properties, e.g. the weldability, of materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/02—Iron or ferrous alloys
    • B23K2103/04—Steel or steel alloys
    • B23K2103/05—Stainless steel

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
  • Investigating And Analyzing Materials By Characteristic Methods (AREA)

Abstract

Disclosed is a method to test causticity at welded area of a stainless steel. In the method, a test piece(2) is manufactured by arc welding. The test piece(2) is heated in a nitric acid of 60 to the extent of 80 %, and the removed area by the causticity is measured. Next, a stretch test is performed by 0.5 to the extent of 5.0 mm/min of stretch speed, and measure a maximum stretch stiffness and a stretch ratio. Next, the maximum stretch stiffness and a stretch ratio are compared with those of an unheated piece. Thereby, the causticity at welded area of the stainless steel is accurately acquired.

Description

스테인레스강 용접부의 입계부식성 시험방법Intergranular Corrosion Test Method of Stainless Steel Weldment

제1도는 본 발명에 의한 용접부의 입계부식시험용 시험편을 나타내는 사시도,1 is a perspective view showing a test piece for grain boundary corrosion test of the weld zone according to the present invention,

제2도는 본 발명에 의한 용접부의 입계부식시험용 시험편을 나타내는 평면도,2 is a plan view showing a test piece for grain boundary corrosion test of the weld zone according to the present invention,

제3도는 본 발명에 의한 용접부의 입계부식시험용 시험편을 나타내는 정면도이다.3 is a front view showing a test piece for grain boundary corrosion test of a welded part according to the present invention.

[산업상의 이용분야][Industrial use]

본 발명은 스테인레스강 용접부의 입계부식성 시험방법에 관한 것으로서, 보다 상세하게는 모재의 전면부식성과 용접부의 입계부식성을 정량적으로 측정하여 용접부의 용착금속과 용접열 영향부 및 모재에 대한 국소적인 부분의 입계부식성을 정확히 판독할 수 있게 하는 스테인레스강 용접부의 입계부식성 시험방법에 관한 것이다.The present invention relates to a method for testing the intergranular corrosion of stainless steel welds, and more specifically, to measure the front and the intergranular corrosion of the base material quantitatively to measure the weld metal, the weld heat affected zone and the local parts of the base material. The present invention relates to a method for testing the intergranular corrosion of stainless steel welds to accurately read the intergranular corrosion.

[종래기술][Private Technology]

일반적으로 스테인레스강의 아아크용접법은 피복아아크용접법과 가스텅스텐 아아크용접법, 그리고 가스메탈 아아크용접법 및 서브머지드 아아크용접법 등으로 구별된다.In general, the arc welding method of stainless steel is classified into coated arc welding method, gas tungsten arc welding method, gas metal arc welding method and submerged arc welding method.

특히, 상기한 가스텅스텐 아아크용접은 아르곤, 헬륨 등의 블활성가스의 분위기 중에서 텅스텐전극의 아아크로 용접을 행한다.In particular, the gas tungsten arc welding is performed by arc welding of a tungsten electrode in an atmosphere of a deactivated gas such as argon or helium.

이와 같은 가스텅스텐 아아크용접에서의 텅스텐전극은 비소모성으로 열원을 제공하고, 아르곤 및 헬륨등의 불활성가스는 용접부분의 공기를 불어내어 텅스텐 전극과 가열된 부분의 산화를 방지하는 역할을 한다.The tungsten electrode in the gas tungsten arc welding provides a heat source non-consumable, and the inert gas such as argon and helium blows the air in the welded portion to prevent oxidation of the tungsten electrode and the heated portion.

한편, 상기한 바와 같은 스테인레스강 용접부의 입계부식성을 시험하기 위하여는 보통 황산·황산동시험이 널리 채택되고 있는데, 이러한 방법은 황산동((CuSO4)·5H2O) 100g을 황산(H2SO4) 용액 100ml 중에 가하고, 이를 증류수에 의해 1000ml로 정용화한 황산·황산동 용액을 제조한다.On the other hand, there to test the grain boundary corrosion resistance of a stainless steel weld is usually sulfuric acid, copper sulfate test is widely adopted as described above, this method is the copper sulfate ((CuSO 4) · 5H 2 O) 100g of sulfuric acid (H 2 SO 4 ) Is added to 100 ml of a solution, and a sulfuric acid-copper sulfate solution is prepared by diagnosing it with 1000 ml with distilled water.

이와 같이 제조된 시험용액중의 부식조에 시험편을 넣어서 연속 24시간 가열하며, 이때 부식조내에 상기 시험편과 동종의 동편(銅片)을 넣어 가열이 종료된 후에도 잔존되게 한다.A test piece is put into a corrosion bath in the test solution thus prepared and heated for 24 hours continuously. At this time, a copper piece of the same kind as the test piece is placed in the corrosion bath so that it remains even after the heating is completed.

한편, 가열에 의한 비등의 종료 후 시험편의 굴곡면 외측을 확대경, 또는 현미경으로 입계부식 균열의 발생 여부를 관찰한다.On the other hand, after completion | finish of boiling by heating, the outside of the curved surface of a test piece is observed whether a grain boundary corrosion crack is produced with a magnifying glass or a microscope.

그런데, 상기한 바와 같은 입계부식성 시험방법은 크롬탄화물의 석출에 따른 결정입계의 부식성을 관찰하기 때문에 고용화 열처리된 스테인레스강과 이 스테인레스강을 650℃에서 2시간 동안 예민화 열처리한 강에 대하여는 용이한 부식여부의 판독이 가능하지만 굴곡가공에 대한 균열과 용접부의 입계부식에 대한 균열을 식별할 수 없어 용접부의 입계부식성 즉, 용접부의 융착금속부와 용접열 영향부 및 모재의 극소적인 부분에 대한 정확한 판독이 불가능한 단점이 있다.However, the above-described grain boundary corrosion test method is easy to observe the solidity of the heat-treated heat-treated stainless steel and sensitized heat-treated stainless steel at 650 ℃ for 2 hours because it observes the corrosion of the grain boundary due to the precipitation of chromium carbide Corrosion can be read, but cracks on bending and cracks on intergranular corrosion of welds can be discerned. There is a disadvantage that cannot be read.

[발명의 요약][Summary of invention]

본 발명은 상기한 바와 같은 종래의 단점을 해소하기 위하여 안출된 것으로서, 본 발명의 목적은 모재의 전면부식성과 용접부의 입계부식성을 정량적으로 측정함으로써, 용접부의 융착금속과 용접열 영향부 및 모재에 대한 국소적인 부분의 입계부식성을 정확히 판독할 수 있게 하는 스테인레스강 용접부의 입계부식성 시험방법을 제공하는데 있다.The present invention has been made in order to solve the above-mentioned disadvantages, the object of the present invention is to quantitatively measure the front corrosion of the base material and the intergranular corrosion of the weld, to the weld metal of the weld and the heat affected zone and the base material The present invention provides a method for testing the intergranular corrosion of stainless steel welds to accurately read the intergranular corrosion of localized parts.

이를 실현하기 위하여 본 발명은 가스텅스텐 아아크용접을 행한 시험편을 제조하고, 이 시험편을 60∼80%의 비등(沸謄) 질산용액 중에서 43∼53시간 동안 가열하는 비등 부식을 1∼5회 실시하고, 시험편의 부식감량을 1∼5회 측정하고, 0.5∼5.0mm/min의 인장속도로 인장시험을 행하고 최고인장강도와 연신율을 측정하고, 이때 측정된 시험편의 최고 인장강도 및 연신율과 부식시키지 않은 시험편의 최고인장강도 및 연신율을 비교하여 최고인장강도 및 연신율의 변화값을 구함으로써, 용접부 입계의 부식정도를 판독함을 특징으로 하는 스테인레스강 용접부의 입계부식성 시험방법을 제공한다.In order to realize this, the present invention is to prepare a test piece subjected to gas tungsten arc welding, and subjected to boiling corrosion 1 to 5 times by heating the test piece in a 60 to 80% boiling nitric acid solution for 43 to 53 hours. , The loss of corrosion of the test piece was measured 1 to 5 times, the tensile test was carried out at a tensile speed of 0.5 to 5.0 mm / min, and the maximum tensile strength and elongation were measured. The grain boundary corrosion test method of the stainless steel welded part is provided by comparing the maximum tensile strength and elongation of the steel and obtaining the change of the maximum tensile strength and elongation.

이하, 본 발명의 바람직한 실시예를 첨부한 도면에 따라서 더욱 상세히 설명하기로 한다.Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[실시예]EXAMPLE

본 발명은 제1도에 도시한 바와 같은 시험편(2)을 제조하는데, 이와 같은 시험편(2)은 직사각형을 형상을 취하는 시험편(2)의 장변부 양쪽에 V자형, 또는 U자형상을 취하며, 시험편(2) 폭에 대한 3∼20% 범위를 갖는 노치(4)를 형성하여 부식시험부위를 지정한다.The present invention manufactures a test piece 2 as shown in FIG. 1, which has a V-shape or a U-shape on both sides of a long side of the test piece 2 taking a rectangular shape. , A notch (4) having a range of 3 to 20% of the width of the test piece (2) is formed to designate the corrosion test site.

이때, 노치(4) 깊이가 시험편(2)의 3% 이하로 되면 균열이 발생되지 않고, 노치(4)의 깊이가 시험편(2)폭의 20% 이상이 되면 시험편(2)의 파단 길이가 짧아 부식취석에 대한 충분한 효과를 볼 수 없기 때문에 노치(4) 깊이를 시험편(2) 폭에 대하여 3∼20% 범위로 한정하는 것이 바람직하다.At this time, when the depth of the notch 4 becomes 3% or less of the test piece 2, no crack is generated. When the depth of the notch 4 becomes 20% or more of the width of the test piece 2, the fracture length of the test piece 2 is increased. It is preferable to limit the depth of the notch 4 to 3 to 20% of the width of the test piece 2 because it is short and a sufficient effect on corrosion quarrying cannot be seen.

한편, 상기한 바와 같은 시험편(2)에 시험편(2)을 인장할 방향의 직각방향으로 진행하여 가스텅스텐 아아크용접을 행한다.On the other hand, gas tungsten arc welding is performed on the test piece 2 as described above in the direction perpendicular to the direction in which the test piece 2 is to be tensioned.

이때, 시험편(2)의 두께가 0.8mm일 경우에는 용접전류의 범위를 25∼50Amp로 하고, 시험편(2)의 두께가 1.0mm일 때에는 용접전류의 범위를 30∼75Amp로 하며, 시험편(2)의 두께가 2.5mm일 때에는 용접전류의 범위를 120-250Amp로 한다.At this time, when the thickness of the test piece 2 is 0.8 mm, the range of welding current is 25 to 50 Amp. When the thickness of the test piece 2 is 1.0 mm, the range of welding current is 30 to 75 Amp. If the thickness of) is 2.5mm, the range of welding current is 120-250Amp.

이와 같은 용접전류의 변화 상태를 표 1에 표시한다Table 1 shows the changes in the welding current.

[표 1] TABLE 1

(단, N1, N2는 고질소강을 나타낸다.)(However, N 1 , N 2 represents high nitrogen steel.)

이때, 용접전류를 25Amp 이하로 하면 용입(熔入)이 깊지않아 백비드(Back bead)가 나타나지 않으며, 용접전류를 250Amp 이상으로 하면 용착금속이 하부로 녹아내리거나 시험편(2)에 구멍이 뚫려서 비교대상재로서의 역할을 하지 못하므로 0.8mm의 두께인 시험편(2)에 대한 용접전류를 25∼250Amp 범위로 한정하는 것이 바람직하다.At this time, if the welding current is 25Amp or less, the penetration is not deep and no back bead appears.If the welding current is 250Amp or more, the weld metal melts to the bottom or a hole is formed in the test piece (2). Since it does not play a role as a comparative material, it is preferable to limit the welding current to the test piece 2 having a thickness of 0.8 mm in the range of 25 to 250 Amp.

또, 상기한 바와 같이 제조된 시험편(2)을 60∼80%의 비등(沸謄) 질산용액 중에서 43∼53시간 동안 가열하는 비등 부식을 1∼5회 실시하고, 시험편(2)의 부식감량을 1∼5회 측정한다.Further, the test piece 2 prepared as described above was subjected to boiling corrosion 1 to 5 times in a 60 to 80% boiling nitric acid solution for 43 to 53 hours, thereby reducing the corrosion of the test piece 2. Measure 1 to 5 times.

이때, 질산용액은 60% 이하의 농도에서 부식속도가 낮고, 80% 이상의 농도에서 부식취성이 포화상태를 이루기 때문에 질산용액의 농도를 60∼80%로 하고, 부식시간을 43∼53시간으로 한정하는 것이 바람직하다.At this time, the nitric acid solution has a low corrosion rate at a concentration of 60% or less, and the corrosion brittleness is saturated at a concentration of 80% or more, so the concentration of the nitric acid solution is 60 to 80% and the corrosion time is limited to 43 to 53 hours. It is desirable to.

그리고, 부식감량을 표면적(㎡)과 부식시간(h)으로 나누어 부식속도(g/㎡·h)를 산출함으로써, 전면 부식성을 판독한다.Then, the corrosion loss (g / m 2 · h) is calculated by dividing the corrosion loss by the surface area (m 2) and the corrosion time (h) to read the entire corrosion resistance.

이와 같이 시험편(2)의 두께와 강종에 따른 부식속도를 표 2에 표시한다.Thus, the corrosion rate according to the thickness and steel grade of the test piece (2) is shown in Table 2.

[표 2] TABLE 2

또, 상기와 같이 부식이 종료된 시험편(2)을 0.5∼5.0mm/min의 인장 속도로 인장시험을 행하여 최고인장강도와 연신율을 측정한다In addition, the tensile strength test and the elongation of the test piece (2) after the corrosion is completed at the tensile speed of 0.5 to 5.0mm / min is measured as described above.

이때, 시험편(2)의 인장속도가 0.5mm/min 이하일 경우에는 인장시간이 너무 오래 걸려 취성이 제대로 나타나지 않으며, 5.0mm/min 이상일 때에는 급속한 시험편(2)의 파괴가 진행되기 때문에 시험편(2)의 인장속도를 0.5∼5.0mm/min으로 한정하는 것이 바람직하다.At this time, when the tensile speed of the test piece 2 is 0.5 mm / min or less, the tensile time is too long, so brittleness is not properly observed. When the test piece 2 is 5.0 mm / min or more, the rapid test piece 2 breaks down, so that the test piece 2 It is preferable to limit the tensile velocity of to 0.5 to 5.0 mm / min.

이와 같은 인장속도에 따른 시험편(2)을 인장하여 시험결과를 표 3에 표시한다.The test results (2) according to the tensile speed as described above is shown in Table 3.

[표 3] TABLE 3

한편, 상기한 바와 같은 조건에 의해 인장된 시험편(2)과 부식시키지 않은 시험편(2)의 인장시험치를 정량적으로 하여 표 4에 표시한다.On the other hand, the tensile test value of the test piece (2) and the test piece (2) that is not corroded under the conditions as described above quantitatively shown in Table 4.

[표 4] TABLE 4

(단, 연신율.T는 원점에서 파단선까지의 전체연신율이고,(Elongation rate, T is the total elongation from the origin to the break line,

연신율.U는 윈점에서 최고인장강도까지의 균일연신율임.)Elongation, U is the uniform elongation from the win point to the highest tensile strength.)

[발명의 효과][Effects of the Invention]

상기한 바와 같은 본 발명에 의한 스테인레스강 용접부의 입계부식성 시험방법은 모재의 전면부식성과 용접부의 입계부식성을 정량적으로 측정함으로써, 용접부의 융착금속과 용접열 영향부 및 모재에 대한 국소적인 부분의 입계부식성을 정확히 판독할 수 있게 하는데 그 이점이 있다.The grain boundary corrosion test method of the stainless steel welded portion according to the present invention as described above quantitatively measures the front side corrosion of the base material and the grain boundary corrosion resistance of the weld, thereby the grain boundary of the welded metal of the weld and the heat affected zone and the local part of the base material This has the advantage of enabling accurate readings of corrosiveness.

Claims (1)

가스텅스텐 아아크용접을 행한 시험편(2)을 제조하고, 이 시험편(2)을 60∼80%의 비등(沸騰) 질산용액중에서 43∼53시간 동안 가열하는 비등 부식을 1∼5회 실시하고, 시험편(2)의 부식감량을 1∼5회 측정하고, 0.5∼5.0mm/min의 인장속도로 인장시험을 행하여 최고인장강도와 연신율을 측정하고, 이때 측정된 시험편(2)의 최고인장강도 및 연신율과 부식시키지 않은 시험편(2)의 최고인장강도 및 연신율을 비교하여 최고인장강도 및 연신율의 변화값을 구함으로써, 용접부 입계의 부식정도를 판독함을 특징으로 하는 스테인레스강 용접부의 입계부식성 시험방법.A test piece (2) subjected to gas tungsten arc welding was prepared, and the test piece was subjected to boiling corrosion 1 to 5 times by heating the test piece (2) in a 60 to 80% boiling nitric acid solution for 43 to 53 hours. Corrosion loss of (2) was measured 1 to 5 times, tensile test was performed at a tensile speed of 0.5 to 5.0 mm / min, and the maximum tensile strength and elongation were measured. At this time, the maximum tensile strength and elongation of test piece (2) and A method for testing the intergranular corrosion resistance of a stainless steel weld, characterized by reading the corrosion degree of the grain boundary of the weld by comparing the highest tensile strength and elongation of the test specimen (2) which is not corroded to obtain the change in the maximum tensile strength and elongation.
KR1019940039361A 1994-12-30 1994-12-30 Corrosion testing method for grain boundary of welding stainless steel KR0122116B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1019940039361A KR0122116B1 (en) 1994-12-30 1994-12-30 Corrosion testing method for grain boundary of welding stainless steel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1019940039361A KR0122116B1 (en) 1994-12-30 1994-12-30 Corrosion testing method for grain boundary of welding stainless steel

Publications (2)

Publication Number Publication Date
KR960021354A KR960021354A (en) 1996-07-18
KR0122116B1 true KR0122116B1 (en) 1997-12-04

Family

ID=19405470

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1019940039361A KR0122116B1 (en) 1994-12-30 1994-12-30 Corrosion testing method for grain boundary of welding stainless steel

Country Status (1)

Country Link
KR (1) KR0122116B1 (en)

Also Published As

Publication number Publication date
KR960021354A (en) 1996-07-18

Similar Documents

Publication Publication Date Title
Cam et al. Determination of mechanical and fracture properties of laser beam welded steel joints
ES2255526T3 (en) ALLOY FOR NICKEL BASED WELDING.
Tavara et al. Influence of nickel on the susceptibility to corrosion fatigue of duplex stainless steel welds
Ambade et al. Shielded metal arc welding of AISI 409M ferritic stainless steel: study on mechanical, intergranular corrosion properties and microstructure analysis
CN112432862A (en) Comprehensive evaluation method for welding thermal crack sensitivity
KR0122116B1 (en) Corrosion testing method for grain boundary of welding stainless steel
US4475963A (en) Method for postweld heat treatment
US20220162723A1 (en) Surface-modifying method for steel material and steel structure
Tshilwane et al. Stress corrosion cracking of laser alloyed 304L stainless steel with Ru in hot chloride solution
Xu et al. Charpy toughness of ERW seam welds
Savage et al. Hydrogen induced cracking in HY-130 steel weldments
Ghosh et al. Control of residual stresses affecting fatigue life of pulsed current gas-metal-arc weld of high-strength aluminum alloy
Afzali et al. Influence of the Plate Thickness on Fracture and Impact Toughness of Duplex Stainless Steels
Henthorne Corrosion testing of weldments
Magalhaes et al. Effect of PWHT on laser-welded duplex stainless steel
Gubeljak et al. Effect of fracture path on the toughness of weld metal
Lee et al. A study on transverse weld cracks in 50 mm thick steel plate with SAW process
Luz et al. Use of double loop electrochemical potentiokinetic reactivation (DL-EPR) to evaluate the sensitization of austenitic steels after welding
Kim et al. Hot corrosion resistance of Ni and Ni-base superalloys
EP0034057B1 (en) Method for postweld heat treatment
JPH0649538A (en) Method for testing hydrogen embrittlement sensitivity of metallic material
JPS5952232B2 (en) Continuous repeated bending treatment method for welded intermediate steel strip
Davies et al. Tensile and shear strength measurements on brazed ‘T’joints used in construction of intra-and intermaxillary hooks
Read Weldment fracture toughness measurements using T-CTOD specimens
Barnby et al. Fatigue properties of a cast steel

Legal Events

Date Code Title Description
A201 Request for examination
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20000826

Year of fee payment: 4

LAPS Lapse due to unpaid annual fee