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Method and instrument for estimating welding performance of steel containing titanium and niobium elements and application of method

A welding performance and element technology, applied in the field of high-strength steel, can solve problems such as wrong design direction, misjudgment of joint hardness and strength, and reduced bearing capacity

Active Publication Date: 2021-02-23
SHOUGANG CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This kind of precipitation strengthening will disappear after actual welding, reducing the local hardness and strength of the welded joint, thereby reducing the bearing capacity and causing great safety hazards (see figure 1 , figure 2 )
[0010] However, the empirical formula for the hardness of the heat-affected zone based on the traditional carbon equivalent formula, such as the Kihara formula (Formula 4), will overestimate the strength of the welded joint of this type of steel, causing scientific and technical workers to misjudge the hardness and strength of the joint. Misdirected design and needs to be corrected

Method used

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  • Method and instrument for estimating welding performance of steel containing titanium and niobium elements and application of method
  • Method and instrument for estimating welding performance of steel containing titanium and niobium elements and application of method
  • Method and instrument for estimating welding performance of steel containing titanium and niobium elements and application of method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053]Example 1: Q700 steel plate, the chemical composition is shown in Table 1, CE=0.386 calculated with (Equation 1), Ceq=0.394 calculated with (Equation 2), P calculated with (Equation 3)cm = 0.162. Substituting Kihara formula (Equation 4) to get Hmax(Formula 4) =302HV.

[0054]Table 1 Test Q700 steel plate chemical composition (Wt%)

[0055] Steel / specification CSi Mn PSMo Ti NB Q700 / 7MM 0.0620.0561.810.0120.0040.110.100.071

[0056]In fact, the highest hardness of the welding heat-affected zone is only 232HV~271HV (Table 2), and the predicted value deviates greatly from the actual value.

[0057]Table 2 Q700 hot influencing area maximum hardness test

[0058]

[0059]CEQs = 0.328 ~ 0.352, CEQS = 0.338 ~ 0.36, P cm S = 0.158 ~ 0.159. Get into the wooden formula (formula 4) to get hmax(Formula 4) = 265HV ~ 280HV, with a higher degree of anastomosis with the measured value.

Embodiment 2

[0060]Example 2: Q600 Steel plate, chemical composition is shown in Table 3, calculated by (formula 1), calculated by (formula 2) to obtain CEQ = 0.332, calculated using (formula 3) to obtain Pcm = 0.153. Get into the wooden formula (formula 4) to get hmax(Formula 4) = 261HV.

[0061]Table 3 Test steel plate Q600 chemical composition (wt%)

[0062] Steel / specification CSi Mn PSTi NB Q600 / 10mm 0.070.211.520.0120.0030.1190.046

[0063]In fact, the highest hardness of the welded heat affected area is only 217 hV ~ 230HV (Table 4), and the predicted value is large.

[0064]Table 4 Q600 maximum hardness test parameters and results

[0065]

[0066]CEQs = 0.269 ~ 0.29, CEQS = 0.278 ~ 0.299, P, 5.278 ~ 0.299, Pcm S = 0.149 ~ 0.151. Get into the wooden formula (formula 4) to get hmax(Formula 4) = 225 ~ 239, with a higher degree of anastomosis with the measured value.

Embodiment 3

[0067]Example 3: Q550D, Q690D Steel plate, chemical composition is shown in Table 3, Q550D Calculated CE = 0.434, calculated by (formula 2), calculated using (formula 3) to calculate Pcm = 0.19. Get into the wooden formula (formula 4) to get hmax(Formula 4) = 326 hV. The Q690D was calculated using (formula 1) to obtain CE = 0.454 with (Equation 2), calculated using (formula 3) to obtain Pcm = 0.208. Get into the wooden formula (formula 4) to get hmax(Formula 4) = 342HV.

[0068]Table 5 Test Steel Q550D, Q690D Chemical Components (WT%)

[0069] Steel / specification CSi Mn PSNi Mo CrCu BTi NB Q550D / 30mm 0.0630.311.500.0070.0020.160.170.290.27--0.0120.046 Q690D / 30mm0.060.291.670.0090.00290.240.190.250.380.00130.0170.054

[0070]In fact, the highest hardness of Q550D welding heat affected zone is only 233HV ~ 276HV (Table 6), and the highest hardness of the Q690D welded heat affected zone is 312HV ~ 348HV (Table 7), and the predicted value has a certain deviation of the actual value.

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Abstract

The invention discloses a method and instrument for estimating the welding performance of steel containing titanium and niobium elements and application of the method. A carbon equivalent correction formula CEs, C<eq>s and P<cm>s increases the negative influence of Ti and Nb on the carbon equivalent, is used for optimizing the chemical components of the microalloy high-strength steel, predicting the hardness of a welding heat affected zone, setting the welding preheating temperature and avoiding welding cracks, and is suitable for design, development and application of microalloy high-strengthsteel and ultrahigh-strength steel products. According to the carbon equivalent estimation method, the hardness value and softening tendency of a welding area can be predicted more accurately, variety development is guided, and the welding process is formulated.

Description

Technical field[0001]The invention belongs to the technical field of high-strength steel, and relates to a method, application and instrument for predicting the welding performance of steel containing titanium and niobium elements. The carbon equivalent correction formula CEs, C of the present inventionEQ s, Pcm s, increase the influence of Ti and Nb on carbon equivalent, used to optimize the chemical composition of microalloy high-strength steel, predict the hardness of welding heat-affected zone, set welding preheating temperature, and avoid welding cracks, suitable for microalloy high-strength steel and ultra-high-strength steel Product design, development and application.Background technique[0002]At present, the traditional concept of using the traditional carbon equivalent formula to guide the design of high-strength steel and the cold-cracking sensitivity index to guide the formulation of the welding process. The strength control technology of welded joints is mainly based on ...

Claims

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Application Information

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IPC IPC(8): B23K31/12
CPCB23K31/12
Inventor 董现春潘辉杨建炜刘新垚王凤会赵英建牟淑坤陈延清张飞虎
Owner SHOUGANG CORPORATION
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