SU1409895A1 - Method of determining tendency of stainless steel to intercrystalline corrosion - Google Patents

Abstract

The invention relates to the field of corrosion resistance testing of metals. The purpose of the invention is to determine the tendency of steel to intergranular corrosion (ICC). The method is carried out as follows. A sample of hardened 12X18H10T stainless steel is placed in an electrochemical cell and polarized from a potentiostat equipped with a special Hz frequency generator. As a corrosive environment, it is advisable to use an electrolyte of one of the compositions: 6-10N. H2S04 + 0.25 - 1n. NaF + 0.04 - 0.5 n. 6-10N, H2SO4 + 0.25 - 1N. NaF + 0.10 - 0.5 n. FeS04; 1-5n. oxalic acid + 1-6n. Hbf A cyclogram of the polarization current is recorded and the propensity for ICC is determined according to the calibration curve. 1 il. i (L

Description

with

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co & 1

The invention relates to the testing of metals for corrosion resistance,

The purpose of the invention is to understand the reliability of the determination of the propensity for ICC, steel 12X18H10T.

The drawing shows a calibration graph for the location of cyclograms of steel 12X18H10T.

The method is carried out as follows.

A sample of hardened 12X18H10T stainless steel with a size of 40-2000 mm is freed from the oxide film and placed as a working electrode in a three-electrode electrochemical cell. The electrodes are connected: working is all aids and compared to the corresponding potentiostat terminals. The potentiostat should be provided with external sweep from a signal generator of a special form (for example, G6-15). Prepare the generator to work on the desired mode. Electrolyte is poured into the cell.

It is advisable to use the electrolyte of one of the compositions:

6-Yun. H S04 + 0.25-1 n. NaF + 0.04 - 0.5 n. CuS04;

6-10H. H S04 + 0.25-lH. NaF + 0.10 - 0.5 n. FeS04;

1-5n, oxalic acid + 1-6n. Hbf

four .

From potentiostat served on the cell

potential midpoint sweep. From the generator (G6-15) a cycling sweep is fed to the electrodes. Record, mA / SAg

ts

There is a cyclogram of polarization current. By . The test results are used to build a calibration graph shown in the drawing. This graph shows two areas: I - the region of the cyclograms of 12X18H1OT steel resistant to the ICC and II - the region of the cyclograms of the steel inclined to the ICC. The determination of the propensity for ICC is carried out according to the drawing schedule after 3-20 minutes, cycling the potential on the samples.

25

Claims (1)

15 claims 0 five The method of determining the tendency of stainless steels to intergranular corrosion (ICC), Tio which place the sample in an acidic electrolyte containing halide ions in an amount of 0.2-7 n. polarize it with a direct current until a predetermined potential is reached, modulate the direct current with an alternating current with a frequency of Hz, record the anode current, and determine the propensity for ICC that is different, in order to increase the accuracy of determining the propensity for ICC of steel 12X18H10T , as the electrolyte use a solution, optionally containing 6-Yun, NlZol, - .OA. T 0 . and 0.04-Zn. Cu ions or oxalate ions - 0.04-Zn. or 0.1-2n. five Fe ions  about. addiction to ICC judgment t according to the polarization current density at potentials from +0.2 to +0.4 V. N.V.E. f, M VNIIPI Order 34 71 /, 38 Random polygons pr-tie, g; Uzhgorod, st. Project, 4 Circulation 847 Subscription