CN201069428Y - Measuring device for groove corrosion depth in welded pipe weld zone - Google Patents

Abstract

The utility model discloses a device for measuring groove corrosion depth in a welded seam area of a welded pipe. The measuring device comprises: a micrometer, including a micrometer screw and a probe. The probe is arranged at the bottom end of the micrometer screw and is connected with the micrometer screw. Fixed; lifting and clamping parts, including workbench, slide bar and fixture, the slide bar is set on the workbench, and the lower end is fixed vertically with the workbench; the fixture is set on the slide bar, one end is connected with the slide bar, and the other end is clamped with the micrometer connection; the sample stage is set on the upper surface of the workbench; the path determination table is provided with wires at the input and output ends, and are respectively connected to the micrometer and the sample table through the wires. The measuring device reads directly through the micrometer, the measuring data is accurate and reliable, and can perform multi-point measurement according to the needs, taking the average value as the data is more accurate; the operation is simple, no professional personnel are required, and the measuring period is greatly shortened; in addition, the measuring device is cheap , which not only saves the measurement cost, but also increases the economic effect.

Description

Measuring device for groove corrosion depth in welded pipe weld zone

technical field

The utility model relates to a detection device for groove corrosion performance in a welded seam area of a welded pipe, in particular to a groove corrosion depth measurement device in the welded seam area of a welded pipe, which can quickly measure the groove corrosion depth.

Background technique

Due to the significant difference in the microcomposition, inclusion content and microstructure between the weld zone of the welded pipe welded by high frequency resistance welding (HF-ERW) and the base metal, the potential of the weld zone is lower than that of the base metal. When there is an appropriate amount of corrosive medium in the weld zone, the potential difference between them will cause an electrochemical primary battery to form between the weld zone and the base metal, resulting in severe local groove corrosion in the weld. Through the research, it is found that the essence of groove corrosion is the galvanic corrosion caused by the local phase electrochemical inhomogeneity of the welded pipe weld zone of high frequency resistance welding (HF-ERW) in the environmental medium or transmission medium, so it is necessary to analyze the weld zone Groove corrosion performance was tested. At present, the trench corrosion performance is characterized by the trench corrosion sensitivity coefficient, which can be determined by electrochemical constant potential polarization method. The method is to first package a weld sample of a certain size and then place it in a 3.5% NaCl solution, and conduct polarized electrolysis by applying a constant potential of -550mV (vs. SCE). After continuous testing for 144 hours, remove the Corrosion products, and calculate the average corrosion depth d1 of the sample according to the weight loss per unit area, and then measure the actual depth d2 of the corrosion groove, and finally calculate the groove corrosion sensitivity coefficient α, the calculation formula is α=d2 /d1. At present, there is no special equipment or device for actually measuring the depth of groove corrosion in the weld zone of welded pipes at home and abroad. The commonly used measurement method is: firstly prepare a cross-sectional metallographic sample of the corroded sample, and then use a metallographic microscope or a scanning electron microscope to magnify and observe and estimate. However, this measurement method has the following disadvantages:

(1) It is difficult to prepare the metallographic specimen of the cross-section of the corrosion sample, the preparation process is cumbersome, time-consuming and laborious, and the requirements are high, otherwise it will directly lead to the increase of the measurement error. (2) The measurement points are limited. Each metallographic sample can only be used for the data measurement of one part of the groove, but the corrosion depth information of different parts along the groove cannot be obtained. For each additional test point, it is necessary to prepare a (or Once) metallographic sample, which greatly increases the workload of sample preparation and affects work efficiency. (3) The depth measurement generally uses a metallographic microscope or a scanning electron microscope. The scanning electron microscope is a large-scale analytical instrument and equipment, and the measurement cost is relatively high, and generally requires professional operation, and it is difficult to measure anytime and anywhere as needed. (4) Since the surface of the corrosion sample is usually uneven, it is difficult to determine the reference plane for groove depth measurement, and only a position can be roughly selected according to the observed field of view, thereby reducing the accuracy of the measurement data. In addition, this method uses estimation, which makes it difficult for the data to be accurate to 0.01mm. However, in general, the groove corrosion depth of the sample base material and weld seam is small, within 0.10mm, so this measurement method There is a large measurement error.

Utility model content

Aiming at the shortcomings of the above-mentioned measurement sample preparation difficulties, limited measurement points, difficult operation, high measurement costs and large measurement errors existing in the prior art, the purpose of this utility model is to provide a groove corrosion depth measurement device in the weld zone of welded pipes , the measuring device is simple in structure and easy to use, not only can improve the measuring speed and precision, but also reduce the measuring cost.

In order to achieve the above object, the utility model adopts the following technical solutions:

The device for measuring the depth of groove corrosion in the welded seam area of the welded pipe includes: a micrometer, including a micrometer screw and a probe, the probe is arranged at the bottom of the micrometer screw, and is connected and fixed with the micrometer screw; the lifting and clamping parts include a working table , slide bar and fixture, the slide bar is set on the workbench, and the lower end is fixed vertically with the workbench; the fixture is set on the slide bar, one end is connected with the slide bar, and the other end is clamped and connected with the micrometer; the sample table is set on the workbench The upper surface; the path determination table, the input and output terminals are respectively provided with wires, and are respectively connected to the micrometer and the sample stage through the wires.

The center of the bottom end of the micrometer screw has a circular hole, and one end of the probe is arranged in the circular hole; the radial surface of the micrometer screw is also provided with a screw hole, which communicates with the circular hole, and is passed through by the tightening bolt. The screw hole and the probe are tight and fixed.

One end of the clamp is provided with a round hole, which is sleeved on the slide bar through the round hole, and is fastened and fixed with the slide bar by the jacking bolt. The other end of the clamp clamps the micrometer, and is clamped and fixed by the fixing bolt and the micrometer.

The bottom of the sample table is provided with a horizontal adjustment bolt, the upper end of the horizontal adjustment bolt is connected with the sample table, and the lower end is arranged on the upper surface of the workbench; the upper surface of the sample table is also provided with a level.

The material of the probe and the sample platform is stainless steel.

The material of the fixture and workbench is polytetrafluoroethylene.

The path determination table includes a power supply, a resistor and an ammeter. The positive pole of the power supply is connected in series with the resistor and the ammeter respectively, and is connected to the micrometer through a wire, and the negative pole of the power supply is connected to the sample stage through a wire; the ammeter also has a pointer.

In the above technical solution, the device for measuring the groove corrosion depth of the welded pipe weld zone of the present invention includes: a micrometer, including a micrometer screw and a probe, and the probe is arranged at the bottom end of the micrometer screw, and is connected and fixed with the micrometer screw ;Elevating and clamping parts, including workbench, slide bar and fixture, the slide bar is set on the workbench, the lower end is fixed vertically with the workbench; the fixture is set on the slide bar, one end is connected with the slide bar, and the other end is clamped and connected with the micrometer The sample stage is set on the upper surface of the workbench; the path determination table is provided with wires at the input and output ends, and is respectively connected to the micrometer and the sample table through the wires. The measuring device has a simple structure, is easy to use, and can be directly read by a micrometer, and the measurement data is accurate and reliable, and can perform multi-point measurement according to the needs, and the data is more accurate; and the operation is simple, no professional personnel are required, and the measurement cycle is greatly shortened; in addition, the measurement The low cost of the device not only saves the measurement cost, but also increases the economic effect.

Description of drawings

Fig. 1 is the structure schematic diagram of the groove corrosion depth measuring device of welded pipe weld zone of the utility model;

Fig. 2 is a schematic diagram of the enlarged structure of part A of the measuring device shown in Fig. 1;

Fig. 3 is a schematic circuit diagram of the path determination table of the measuring device of the present invention.

Detailed ways

The technical scheme of the utility model is further described below in conjunction with the accompanying drawings and embodiments.

Please refer to Fig. 1, the groove corrosion depth measurement device 10 of the welded pipe weld zone of the present utility model includes a micrometer 11, a lifting clamping part 12, a sample table 13 and a path determination table 14, and the micrometer 11 can be a common one commonly used at present. As for the mechanical micrometer or the digital display micrometer, only the measuring anvil and the frame part (not shown in the figure) of the micrometer 11 are removed. In this way, the micrometer 11 includes a micrometer screw 111, a fine-tuning knob 112, a knob 113 and a scale 114, as shown in Fig. mm, the depth is 3-5mm, and a screw hole (not shown in the figure) with an inner diameter of 1-1.5mm is opened on the radial surface 1.5-3mm away from the bottom end of the micrometer screw 111, and the screw hole is connected with the round hole 115 connected. The micrometer 11 also includes a probe 116. The material of the probe 116 is stainless steel. Since the width of the corrosion groove in the weld zone of the welded pipe generally ranges from 0.20 to 1.00 mm and the depth ranges from 0.01 to 1.00 mm, the size of the probe is very small. The diameter of the needle 116 is 0.05-0.5 mm. The upper end of the probe 116 is vertically inserted into the circular hole 115, and the probe 116 is tightened with the screw hole by the tightening bolt 117, and the probe 116 is fixed on the bottom end of the micrometer screw 111, and the lower end of the probe 116 extends out of the circular hole 115 and face straight down. Please refer to FIG. 1 again, the lifting and clamping part 12 includes a workbench 121, a slide bar 122 and a clamp 123. The material of the workbench 121 is polytetrafluoroethylene, and the upper surface is smooth and flat. The slide bar 122 is arranged on the workbench 121, and the lower end is vertically fixed to the workbench 121; the material of the fixture 123 is also polytetrafluoroethylene, and the left end of the fixture 123 clamps the micrometer 11, and is clamped and fixed by the fixing bolt 124 and the micrometer 11, The right end of the clamp 123 has a vertical circular hole (not shown in the figure), which is sleeved on the slide bar 122 through the circular hole, and can move up and down on the slide bar 122, and is connected to the slide bar by the tightening bolt 117. 122 is tightly fixed, so that the height of the micrometer 11 can be adjusted according to the actual height of the sample. The sample table 13 is arranged on the workbench 121. The material of the sample table 13 is stainless steel. The sample table 13 shown in Fig. 1 is a cuboid, and the four corners of the bottom are respectively provided with a horizontal adjustment bolt 131, and the upper end of the horizontal adjustment bolt 131 is connected with the sample table 13, and the lower end is arranged on the upper surface of the workbench 121; the sample table 13 A bubble level 132 is also provided on the upper surface, through which the level adjusting bolt 131 is measured and adjusted to keep the upper surface of the sample stage 13 level. Please combine as shown in Figure 3, the path determination table 14 includes a power supply 141, a resistor 142 and an ammeter 143, the positive pole of the power supply 141 is connected in series with the resistor 142 and the ammeter 143 respectively, and is connected to the upper end of the micrometer 11 through a wire 15, and the negative pole of the power supply 141 is connected through a wire 15 is connected with the sample stage 13, and the appearance of the wire 15 is insulated.

When measuring, take a mechanical micrometer as an example, first fix the micrometer 11 at an appropriate initial height through the clamp 123, then turn the knob 113 and the fine-tuning knob 112 of the micrometer 11 to lower the micrometer screw 111, and observe the path determination table 14 , since the probe 116 and the sample stage 13 are all stainless steel, and the micrometer 11 is also metal, which is a conductive material, when the pointer 144 (see Figure 1) of the ammeter 143 of the path determination table 14 deflects, it means that the path The judgment table 14, the micrometer 11, and the sample stage 13 have been conducted to form a loop, that is, the probe 116 of the micrometer screw 111 is just in vertical contact with the sample stage 13, and the initial reading h1( If a digital display micrometer is used, it can be directly adjusted to zero, i.e. h1=0); then the micrometer screw 111 is adjusted up, and the welded pipe sample (not shown in the figure) ) on the sample table 13, and align the probe 116 with the groove of the sample weld area, then lower the micrometer screw 111, and observe the path judgment table 14, when the pointer 144 deflects, it indicates that the probe The needle 116 just touches the bottom of the groove in the weld area of the sample, and records the reading h2 displayed by the scale 114 of the micrometer 11 at this time, and the initial thickness of the groove in the weld area of the sample can be obtained by calculation as h2-h1; then The sample is subjected to an electrochemical constant potential polarization test, and the average corrosion depth d1 of the sample is calculated through the weight loss of the sample, and then the sample after the electrochemical test is placed on the sample stage 13 again. 10 Measure the bottom of the groove in the weld area of the sample again, and record the reading h3 displayed on the scale 114 of the micrometer 11. At this time, the actual depth of the corrosion groove in the weld area of the sample can be obtained by calculation as d2 '=h3-h2-h1, and then the trench corrosion sensitivity coefficient α=d2'/d1 can be obtained. What needs to be explained here is that during the actual measurement of h2 and h3, since the grooves in the weld area of the sample are usually uneven, the probe 116 cannot just come into contact with the bottom of the groove of the sample at one time, so it can be Through visual judgment and adjustment of the sample, the probe 116 can be in contact with the bottom of the sample groove; in addition, the sample groove can be measured at multiple points and the measured readings are compared to finally obtain The most accurate h2, h3 values, thus ensuring the measurement accuracy.

Using the measuring device 10 to measure the groove corrosion depth in the welded seam area of the welded pipe has high measurement accuracy and fast speed. It used to take at least 1 hour to complete the measurement of one point of the sample, but now it only takes 1 hour to complete the measurement of multiple points of the sample. Minutes greatly shortens the measurement period, and requires no professionals, and the operation is very simple; in addition, the cost of the measuring device 10 is not more than 400 yuan, and each measurement does not require any other expenses, which not only reduces the cost, but also improves economic benefits.

Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the utility model, rather than as a limitation to the utility model, as long as within the spirit of the utility model, the above-mentioned The changes and modifications of the embodiments will all fall within the scope of the claims of the present utility model.

Claims (7)

1. a welded tube weld metal zone guttering corrosion depth measurement device is characterized in that,

This measurement mechanism comprises:

Milscale comprises micrometric screw and probe, and probe is located at the bottom of micrometric screw, and is connected and fixed with micrometric screw;

The lifting clamping part comprises worktable, slide bar and anchor clamps, and slide bar is located on the worktable, lower end and worktable vertical fixing; Anchor clamps are located on the slide bar, and an end is connected with slide bar, and the other end clamps with milscale and is connected;

Sample bench is located at worktable upper surface;

The path decision table, input, output terminal are respectively equipped with lead, and are connected respectively to milscale and sample bench by lead.

2. welded tube as claimed in claim 1 weld metal zone guttering corrosion depth measurement device is characterized in that:

Described micrometric screw bottom center has circular hole, and described probe one end is located in the circular hole; The micrometric screw radial surface also has screw, and communicates with circular hole, passes screw and probe holds out against and fixing by puller bolt.

3. welded tube as claimed in claim 1 weld metal zone guttering corrosion depth measurement device is characterized in that:

Described anchor clamps one end is provided with circular hole, on slide bar, and holds out against fixingly by puller bolt and slide bar by circle hole sleeve, and the anchor clamps other end is clamped milscale, and is fixedly clamped by set bolt and milscale.

4. welded tube as claimed in claim 1 weld metal zone guttering corrosion depth measurement device is characterized in that:

Described sample bench bottom is provided with horizontal adjustment bolt, and the horizontal adjustment bolt upper end is connected with sample bench, and worktable upper surface is located in the lower end; The sample bench upper surface also is provided with level meter.

5. as claim 1 or 2 or 4 described welded tube weld metal zone guttering corrosion depth measurement devices, it is characterized in that:

The material of described probe and sample bench is a stainless steel.

6. as claim 1 or 3 or 4 described welded tube weld metal zone guttering corrosion depth measurement devices, it is characterized in that:

The material of described anchor clamps and worktable is a teflon.

7. welded tube as claimed in claim 1 weld metal zone guttering corrosion depth measurement device is characterized in that:

Described path decision table comprises power supply, resistance and galvanometer, and positive source is connected with resistance, galvanometer respectively, and is connected with milscale by lead, and power cathode is connected with sample bench by lead; Also be provided with pointer in the galvanometer.

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