CN103542819A - Detection and quality judgment method for strip steel weld surface appearance - Google Patents

Abstract

Disclosed is a detection and quality judgment method for strip steel weld surface appearance. The surface of a weld is scanned by a linear laser; the values such as weld stack height, depression, undercut and misalignment are calculated according to scanned data; the quality of the weld is judged according to the values; accordingly, the surface appearance quality of the weld is judged continuously. The method has the advantages that the surface appearance of the weld can be detected fast and evaluated fast, fast continuous operation of an acid tandem rolling is ensured, and breakage of strip steel is prevented.

Description

A method for detection and quality judgment of strip weld surface morphology

technical field

The invention relates to a strip steel surface detection technology, in particular to a detection and quality judgment method for the surface appearance of a strip steel weld seam.

Background technique

At present, the quality of strip welds is usually judged by on-site operators with naked eyes. This method of discrimination obviously has defects in the experience of operators and judgment standards, and there are problems of low efficiency and inaccurate judgment.

The QCDS system launched by Miebach can realize the automatic detection of the weld seam appearance. The system uses online CCD video to observe the weld seam appearance on the surface of the strip steel, and can provide the topography map of the weld seam surface in time, and the weld seam The concave and misaligned curves allow the operator to judge the quality of the weld and realize the real-time online detection of the surface morphology of the weld. However, the system cannot judge the undercut defect that seriously affects the fracture resistance of the weld, and there are also deficiencies in the judgment standard.

Chinese patent application number 200810229989 discloses "a visual sensor for weld surface quality based on line structured light", which can be used to obtain the topography of the weld surface, but the patent does not mention the specific parameters of the line laser, especially is the scanning frequency, and the technology mentioned in this patent does not have the function of analyzing the test results.

Contents of the invention

The object of the present invention is to provide a method for detecting and quality judging the surface appearance of the welded seam of strip steel, which can quickly detect the appearance of the welded seam surface, and perform rapid evaluation to ensure the continuous and rapid operation of the pickling and cold rolling process , to prevent the occurrence of strip broken belt accidents.

For achieving the above object, technical scheme of the present invention is:

The invention uses a linear laser to scan the surface of the weld seam, draws the surface topography map of the weld seam according to the data obtained by scanning, and at the same time obtains the height, depression, and undercut of the weld seam through calculation according to the obtained scanning data. , misalignment and other values, according to which the surface topography quality of the weld is judged, so as to realize the continuous evaluation of the surface topography quality of the weld.

In the pickling mill, in order to ensure the continuous operation of the rolling mill, the forward strip and the rear strip need to be connected together by welding. The welding quality of the weld is a prerequisite to ensure that the weld can pass through the rolling mill smoothly. Welding defects in welding will directly lead to the fracture of the weld seam in the tension leveling and rolling mill, resulting in a broken belt accident. The welded seam of the strip steel will be subjected to repeated bending for many times before entering the rolling mill. During the repeated bending process, fatigue cracks will be generated in the stress concentration part of the welded seam. The generation of these cracks will directly reduce the strength of the welded seam and affect the welding seam. The defects of weld seam morphology according to the severity of stress concentration on the seam surface include: weld pile height, weld depression, weld undercut and weld misalignment.

Specifically, a method for detecting and quality judging the surface topography of a strip steel weld according to the present invention uses a line laser to scan and detect the topography data of the weld surface in real time, including weld pile height, depression, undercut, lap joint, etc. , calculate the above-mentioned weld seam eigenvalue, statistical eigenvalue maximum position and cross-section characteristics, establish the weld seam appearance evaluation standard, and then detect the weld seam surface appearance in real time, obtain the weld seam surface appearance eigenvalue, and weld seam appearance Comparison of evaluation standards, so as to realize the judgment of weld surface quality; among them:

a) Stack height

The weld heap height indicates the value that the weld is higher than the base metal, and the calculation formula for the equivalent area of the heap is:

$\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="A"\; filenames="120717091415.png"\; state="\{\{state\}\}">A</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; TT</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; mm</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula: h ₁ (i) is the pile height value of the i-th scan data, mm; H is the scanning frequency of the laser, Hz, u is the welding speed, mm/s, TT is the number of scans of the entire weld ;

The pile height of the weld will cause stress concentration at the weld, and the influence of the pile height on the strength of the weld is expressed by the pile height coefficient. The calculation formula of the pile height coefficient is:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="f"\; filenames="120717091415.png"\; state="\{\{state\}\}">f</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; t</span>}}$

In the formula: h ₁ (i) is the stack height value of the i-th scan data, t is the strip thickness, mm;

b) Overlap

Lap joint refers to the amount of misalignment of the strip steel on both sides of the weld, and the calculation formula for the equivalent area of the lap joint is:

$\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="A"\; filenames="120717091415.png"\; state="\{\{state\}\}">A</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; TT</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; mm</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

In the formula: h ₂ (i) is the overlap value of the data obtained from the i-th scan of the weld, mm; H is the scanning frequency, Hz; u is the welding speed, mm/s;

The overlap of the weld will cause stress concentration at the weld, and the influence of the overlap on the strength of the weld is expressed by the overlap coefficient. The calculation formula of the overlap coefficient is:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="f"\; filenames="120717091415.png"\; state="\{\{state\}\}">f</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; t</span>}}$

In the formula: h ₂ (i) is the overlap value at the center line of the section line of the i-th weld, mm; t is the thickness of the strip steel, mm;

c) sunken

Weld sag means that the height of the weld area is lower than the height of the strip base metal. Considering that the overlap of the weld will deepen the stress concentration of the sag, the overlap coefficient is taken into account when calculating the equivalent area of the sag. Inside, the formula for calculating the area of the depression is:

$\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="TT\; f"\; filenames="120717091415.png"\; state="\{\{state\}\}">TT</figure-callout></span><figure-callout\; id="2"\; label="TT\; f"\; filenames="120717091415.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; </span>}}_{}{\mathrm{<span\; class="notranslate">f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; mm</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

h ₃ (i) is the sag value of the i-th scanning data, mm; H is the scanning frequency, Hz; u is the welding speed, mm/s;

d) undercut

The undercut refers to the lowest point within 1mm of the weld fusion line as the undercut value. At the same time, considering the weld pile height and overlap at the undercut position of the weld will aggravate the severity of the stress concentration at the undercut position, so in the calculation When considering the undercut area, the pile height and the lap coefficient are taken into consideration, and the formula for calculating the equivalent area of the total undercut is:

$\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="TT\; f"\; filenames="120717091415.png"\; state="\{\{state\}\}">TT</figure-callout></span><figure-callout\; id="1"\; label="TT\; f"\; filenames="120717091415.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; </span>}}_{}{\mathrm{<span\; class="notranslate">f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="f"\; filenames="120717091415.png"\; state="\{\{state\}\}">f</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; mm</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ;</span>$

Weld appearance evaluation criteria:

serial number Indicator name Threshold Judgment result, such as exceeding the threshold 1 Maximum stack height (h1) 0.2～0.4 Excessive pile height exists in the local area of the weld seam 2 Maximum value of depression (h2) 0.2～0.4 There is a depression in the local area of the weld that exceeds the standard 3 Maximum undercut (h3) 0.2～0.4 There is excessive overlap in the local area of the weld 4 Lap maximum value (h4) 0.2～0.4 Excessive undercut in the local area of the weld 5 Heap equivalent value (A1/A) 0.05～0.2 Weld seam stack height is too large 6 Depression equivalent value (A2/A) 0.05～0.2 Dent too large 7 Equivalent value of undercut (A3/A) 0.05～0.2 undercut too large 8 Lap equivalent value (A4/A) 0.05～0.2 Lap too large 9 Comprehensive evaluation (A3/A+A4/A) 0.1～0.4 There is a serious problem with the weld

Further, the linear laser scans the weld seam appearance, the scanning width ranges from 3 to 10 mm, the height detection range is 50 to 150 mm, and the detection accuracy is 0.001 to 0.005 mm. The detected data is sent to the upper industrial computer in real time, and the scanning The frequency is not lower than 30Hz.

Again, the present invention adopts and comprises linear laser device, trigger switch, upper position industrial computer, lower position PC, line type laser, trigger switch, upper position industrial computer are fixed on the welding machine, moves with welding machine during detection process; Upper position industrial control computer is responsible for Signal collection and processing, filtering the data collected by the linear laser, collecting the data within 3mm of the weld and the two sides of the weld, and sending the data to the lower PC through Ethernet, and the lower PC is welded The seam detection data is analyzed; the trigger switch is used to control the start and stop of the linear laser. When the trigger switch detects the edge of the strip, the linear laser starts to work and continuously sends detection data to the upper industrial computer. After the welding machine is finished, After the trigger switch detects that the welding machine leaves the strip, the trigger switch notifies the upper industrial computer to turn off the linear laser, the laser stops working, and the signal sent by the trigger switch is a pulse signal.

The lower PC is responsible for the analysis and processing of the weld detection data.

Beneficial effects of the present invention

The method of the present invention can effectively detect the defects of the surface appearance of the weld, and the powerful analysis function in the evaluation system can evaluate the quality of the weld in time according to the detection results, and give real-time prompts for the welds with excessive defects, and the system can prevent belt defects Broken bands of steel welds play an important role.

Description of drawings

Fig. 1 is a schematic diagram of weld seam morphology defect-pile height in the present invention.

Fig. 2 is a schematic diagram of the weld seam morphology defect-depression according to the present invention.

Fig. 3 is a schematic diagram of the weld seam morphology defect-undercut according to the present invention.

Fig. 4 is a schematic diagram of the weld seam morphology defect-overlap in the present invention.

Fig. 5 is a schematic diagram of an embodiment of the system of the present invention.

Detailed ways

The present invention will be further described below in conjunction with embodiment.

Referring to Figures 1 to 5, the present invention uses a linear laser to scan the surface of the weld seam, and calculates the weld pile height, depression, undercut, misalignment, etc. according to the data obtained by scanning the surface topography of the weld seam. According to the numerical value, the quality of the surface topography of the weld is judged, so as to realize the continuous evaluation of the quality of the surface topography of the weld.

Referring to Fig. 5, the detection and quality judgment method of the strip weld surface topography of the present invention, adopt and comprise linear laser 1, trigger switch 2, upper industrial computer 3, lower PC 4, linear laser, trigger switch, industrial computer It is fixed on the welding machine and moves with the welding machine during the detection process; the upper industrial computer is responsible for signal collection and processing, filters the data collected by the line laser, and collects the weld seam and the data within 3mm on both sides of the weld seam , send the data to the lower PC through the Ethernet, and analyze the welding seam detection data by the lower PC; the trigger switch is used to control the start and stop of the linear laser, when the trigger switch detects the edge of the strip 5, The linear laser starts to work and continuously sends detection data to the upper industrial computer. After the welding machine ends, the trigger switch detects that the welding machine leaves the strip, and the trigger switch notifies the upper industrial computer to turn off the linear laser. The laser stops working, and the trigger switch sends The signal is a pulse signal.

Example 1

Rolling process of automotive sheet in cold rolling line.

1) The weld detection system consists of a laser, a trigger switch, an upper industrial computer and a lower PC. The laser, trigger switch, and upper industrial computer are fixed on the welding machine and move with the welding machine during the detection process. The lower PC is placed In the operating room, a weld evaluation system is installed in the lower computer.

2) The linear laser adopts CC3000-30 from American Bytewise Company to complete the scanning of the weld seam shape. The scanning width range is 10mm, the height detection range is 30mm, and the detection accuracy is 0.015mm. The detected data are sent to the upper industrial computer in real time , The detection frequency is 30HZ. The upper industrial computer is responsible for the collection and processing of signals, filters the data collected by the laser, collects the data within the range of 3mm (10mm in total) on both sides of the weld and the weld, and sends the data to the lower PC through Ethernet. The PC analyzes the weld inspection data.

3) The trigger switch adopts NPN normally closed model, model ES12-D15C1. When the trigger switch detects the edge of the strip steel, the laser starts to work and continuously sends detection data to the upper industrial computer. After the welding machine is finished, the trigger switch detects the welding machine After leaving the strip, the trigger switch notifies the upper industrial computer to turn off the laser, and the laser stops working.

4) After the lower PC receives the data sent by the detection device, it can display the appearance of the weld seam, calculate the calculation of the characteristic value of the weld seam (pile height, depression, undercut, lap joint), and count the largest part of the characteristic value and the cross-sectional characteristics , Provide the function of weld quality evaluation results, and all detected data are kept in the system.

5) After the lower PC detects the weld signal, it calculates the characteristic value of the weld, and the overall evaluation criteria are shown in Table 1.

Table 1 Evaluation indicators for automotive panels

serial number Indicator name Threshold Judgment result, such as greater than the threshold

1 Maximum stack height (h1) 0.4 There is a stack height exceeding the standard in the local area of the weld" 2 Maximum value of depression (h2) 0.4 There is a depression in the local area of the weld that exceeds the standard 3 Maximum undercut (h3) 0.4 There is excessive overlap in the local area of the weld 4 Maximum overlap (h4) 0.4 Excessive undercut in the local area of the weld 5 Heap equivalent value (A1/A) 0.2 Weld seam stack height is too large 6 Depression equivalent value (A2/A) 0.2 Dent too large 7 Undercut equivalent value (A3/A) 0.2 undercut too large 8 Lap equivalent value (A4/A) 0.2 Lap too large 9 Comprehensive evaluation (A3/A+A4/A) 0.4 There is a serious problem with the weld

6) Use the control indicators in Table 1 to test and evaluate the welds of automobile plates. For welds with good weld quality, the judgment results are qualified. For welds with serious quality problems on the surface of the welds, the inspection and judgment results are unqualified ; From the test results, the weld was in poor shape in the middle, and there were obvious depressions in the edge, and the judgment result was unqualified, but the evaluation result did not attract the attention of the welders. band, and the broken band occurs exactly at the edge where there is an obvious depression.

Example 2

The composition of the system is the same as that of Example 1. For low-grade silicon steel, due to the high brittleness of the material, the evaluation index needs to be adjusted. The adjusted index is shown in Table 2. Using this index to evaluate low-grade silicon steel welds can control the broken belt rate below 1‰.

Table 2 Evaluation indicators for low-grade silicon steel

serial number Index name Threshold Judgment result, if it is greater than the threshold value, then judge 1 Maximum stack height (h1) 0.3 There is a stack height exceeding the standard in the local area of the weld" 2 Maximum value of depression (h2) 0.3 There is a depression in the local area of the weld that exceeds the standard 3 Maximum undercut (h3) 0.3 There is excessive overlap in the local area of the weld 4 Maximum overlap (h4) 0.3 Excessive undercut in the local area of the weld 5 Heap equivalent value (A1/A) 0.2 Weld seam stack height is too large 6 Depression equivalent value (A2/A) 0.15 Dent too large 7 Undercut equivalent value (A3/A) 0.15 undercut too large 8 Lap equivalent value (A4/A) 0.15 Lap too large 9 Comprehensive evaluation (A3/A+A4/A) 0.2 There is a serious problem with the weld

Example 3

The composition of the system is the same as that of Example 1. For medium-grade silicon steel, due to the high silicon content in the material and the high brittleness of the material, it is necessary to strictly limit the defect threshold. The adjusted indicators are shown in Table 3. Using this index to evaluate the weld seam of medium-grade silicon steel can control the broken belt rate below 1‰.

Table 3 Evaluation indicators for low-grade silicon steel

serial number Index name Threshold Judgment result, if it is greater than the threshold value, then judge 1 Maximum stack height (h1) 0.25 There is a stack height exceeding the standard in the local area of the weld" 2 Maximum value of depression (h2) 0.20 There is a depression in the local area of the weld that exceeds the standard 3 Maximum undercut (h3) 0.20 There is excessive overlap in the local area of the weld 4 Maximum overlap (h4) 0.20 Excessive undercut in the local area of the weld 5 Heap equivalent value (A1/A) 0.15 Weld seam stack height is too large 6 Depression equivalent value (A2/A) 0.10 Dent too large 7 Undercut equivalent value (A3/A) 0.10 undercut too large 8 Lap equivalent value (A4/A) 0.10 Lap too large 9 Comprehensive evaluation (A3/A+A4/A) 0.15 There is a serious problem with the weld

Example 4

The composition of the system is the same as that of Example 1. For high-grade silicon steel, due to the high silicon content in the material, the material is very brittle, and the defect threshold needs to be strictly limited. The adjusted indicators are shown in Table 4. Using this index to evaluate high-grade silicon steel welds can control the broken belt rate below 1‰.

Table 4 Evaluation indicators for low-grade silicon steel

serial number Index name Threshold Judgment result, if it is greater than the threshold value, then judge 1 Maximum stack height (h1) 0.2 There is a stack height exceeding the standard in the local area of the weld" 2 Maximum value of depression (h2) 0.2 There is a depression in the local area of the weld that exceeds the standard 3 Maximum undercut (h3) 0.2 There is excessive overlap in the local area of the weld 4 Maximum overlap (h4) 0.2 Excessive undercut in the local area of the weld 5 Heap equivalent value (A1/A) 0.05 Weld seam stack height is too large 6 Depression equivalent value (A2/A) 0.05 Dent too large 7 Undercut equivalent value (A3/A) 0.05 undercut too large 8 Lap equivalent value (A4/A) 0.05 Lap too large 9 Comprehensive evaluation (A3/A+A4/A) 0.10 There is a serious problem with the weld

Claims (3)

1. detection and quality judging method with a steel face of weld pattern, adopt the scanning of Linear Laser device to detect in real time the topographic data of face of weld, detect that weld seam heap is high, the weld defect of depression, undercut, overlap joint, calculate above-mentioned characteristics of weld seam value, the maximum position of statistical characteristics and section feature, set up weld seam pattern evaluation criterion, detect in real time again the pattern of face of weld, obtain the eigenwert of face of weld pattern, compare with weld seam pattern evaluation criterion; Wherein:

A) pile high

Weld seam heap is high represents that weld seam is higher than the numerical value of mother metal, and the computing formula of heap high equivalent weight area is:

$A1=\underset{i=1}{\overset{\mathrm{TT}}{\mathrm{\&Sigma;}}}{h}_1\left(i\right)\&times;\frac{60\&times;u}{H}{\mathrm{mm}}^2$

In formula: h ₁(i) be the high value of heap of the i time scanning the data obtained, mm; H is the frequency of laser scans scanning, Hz, and u is speed of welding, mm/s, TT is the scanning times of whole piece weld seam;

The computing formula of piling high coefficient is:

$f_1=1+\frac{3\&times;h_1\left(i\right)}{t}$

In formula: h ₁(i) be the high value of heap of the i time scanning the data obtained, mm; T is the thickness with steel, mm;

B) overlap joint

Overlap joint refers to the unfitness of butt joint of weld seam two sideband steel, and the computing formula of overlap joint equivalent aera is:

$A2=\underset{i=1}{\overset{\mathrm{TT}}{\mathrm{\&Sigma;}}}{h}_2\left(i\right)\&times;\frac{60\&times;u}{H}{\mathrm{mm}}^2$

In formula: h ₂(i) be the overlap joint value of the i time scanning the data obtained of weld seam, mm; H is the frequency of scanning, Hz; U is speed of welding, mm/s;

Overlapping fraction:

$f_2=1+\frac{5\&times;h_2\left(i\right)}{t}$

In formula: h ₂(i) be the overlap joint value of i root bead seam section line centerline, mm; T is the thickness with steel, mm;

C) depression

Welding depression refers to that the height of welded seam area is lower than the height value with steel mother metal, consider that the overlap joint of weld seam is by the concentrated order of severity of the stress of deepening depression position, therefore when calculating depression equivalent aera, overlapping fraction is taken into account, the computing formula of notch area is:

$A3=\underset{i=1}{\overset{\mathrm{TT}}{\mathrm{\&Sigma;}}}{f}_2\&times;h_3\left(i\right)\&times;\frac{60\&times;u}{H}{\mathrm{mm}}^2$

H ₃(i) be the depression value of the i time scanning the data obtained, mm; H is the frequency of scanning, Hz; U is speed of welding, mm/s;

D) undercut

Undercut refers to that minimum point within the scope of the 1mm of weld-fusion line left and right is as undercut value, weld seam heap height and the overlap joint of considering undercut position will increase the weight of the concentrated order of severity of undercut position stress simultaneously, therefore when calculating undercut area, heap height and overlapping fraction are taken into account, the equivalent aera computing formula of total undercut amount is:

$A4=\underset{i=1}{\overset{\mathrm{TT}}{\mathrm{\&Sigma;}}}{f}_1\&times;f_2\&times;h_3\left(i\right)\&times;\frac{60\&times;u}{H}{\mathrm{mm}}^2;$

Weld seam pattern evaluation criterion:

Sequence number Index name Threshold value Judged result, as exceed threshold value 1 Pile high maximal value (h1) 0.2～0.4 There is high the exceeding standard of heap in weld seam regional area 2 Depression maximal value (h2) 0.2～0.4 Weld seam regional area exists depression to exceed standard 3 Undercut maximal value (h3) 0.2～0.4 Weld seam regional area exists overlap joint to exceed standard 4 Overlap joint maximal value (h4) 0.2～0.4 Weld seam regional area exists undercut to exceed standard 5 Heap high equivalent weight value (A1/A) 0.05～0.2 Weld seam heap is high excessive 6 Depression equivalent value (A2/A) 0.05～0.2 Cave in excessive 7 Undercut equivalent value (A3/A) 0.05～0.2 Undercut is excessive 8 Overlap joint equivalent value (A4/A) 0.05～0.2 Overlap excessive 9 Comprehensive evaluation (A3/A+A4/A) 0.1～0.4 There are serious problems in weld seam

So far, realize with the detection of steel face of weld pattern and the judgement of quality.

2. detection and quality judging method with steel face of weld pattern as claimed in claim 1, it is characterized in that, the scanning of Linear Laser device butt welded seam pattern, sweep length scope is at 3～10mm, height detection scope is at 50～150mm, accuracy of detection is at 0.001～0.005mm, and the data that detect send in upper industrial computer in real time, and laser scans frequency is not less than 30Hz.

3. detection and quality judging method with steel face of weld pattern as claimed in claim 1, it is characterized in that, employing comprises Linear Laser device, trigger switch, upper industrial computer, the next PC, Linear Laser device, trigger switch, upper industrial computer are fixed on welding machine, in testing process, with welding machine, move; Upper industrial computer is responsible for the acquisition and processing of signal, the data that Linear Laser device is collected are filtered, collect the data within the scope of weld seam and weld seam both sides 3mm, these data are sent to the next PC by Ethernet, by the next PC butt welded seam, detect data analysis; Trigger switch is for controlling the startup of line style laser instrument and stopping, when trigger switch detects the edge with steel, Linear Laser device is started working and is sent continuously detection data to upper industrial computer, after welding machine finishes, trigger switch detects welding machine and leaves after band steel, trigger switch notifies upper industrial computer to close line style laser instrument, and laser instrument quits work, and the signal that trigger switch sends is pulse signal.

Images