JPS6212854A - Method for testing lead print of steel - Google Patents

Abstract

PURPOSE:To reduce the time for testing by sticking print paper wet with a sodium hydroxide soln. to the surface to be inspected of a test piece of steel to bring lead into reaction then removing the print paper and immersing the same into a sodium sulfide soln. CONSTITUTION:The surface to be inspected of the test piece of the steel is essentially finished and polished by about 100-600# emery paper. General photographic paper is then immersed into a photographic fixer to thoroughly remove the silver bromide on the surface of the photographic paper; thereafter, the paper is washed and dried to prepare the print paper. The formed print paper is immersed in about 5% sodium hydroxide soln. and is then stuck and tightly adhered to the test surface of the test piece. The print paper is thereafter removed from the test piece and is immersed in about 5% sodium sulfide soln., by which the reacting part of lead is developed as a brown spot on the print paper. The distribution condition of the lead is thus distinctly identified. The time for the testing is thereby reduced.

Description

[Detailed description of the invention] Industrial applications When lead is added to steel for the purpose of improving machinability, etc., its mechanical properties are affected by the amount, shape, and distribution of the added lead. .

The present invention relates to a macroscopic detection method for lead, which is a method for examining the thickness and distribution state of lead grains in such steel materials.

BACKGROUND OF THE INVENTION Conventional printing methods for examining the state of lead dispersion in steel materials are usually carried out after corroding the sample surface in advance, as described below.

(1) Sample preparation/pretreatment: The sample surface is mechanically finished smooth and corroded with a 10% ammonium persulfate solution.

(2) Preparation of printed paper: high-quality paper is soaked in gelatin solution and dried to make printed paper.

(31 Lead print... After immersing the above printed paper in a sodium hydroxide solution, attach it to the sample surface and bring it into close contact.
After sticking for about λ, the printed paper is developed with S in a sodium sulfide solution, and the lead appears as brown spots.

The problem that the invention seeks to solve According to the conventional above procedure, the degree of corrosion on the sample surface.

There are disadvantages in that it requires skill to produce the printed paper, resulting in differences in quality, and it also causes corrosion on the sample surface and takes time and effort to produce the printed paper.

In order to solve the above-mentioned problems, the present invention eliminates the corrosion process of the sample surface and utilizes commercially available photographic paper for printing paper, thereby overcoming the above-mentioned difficulties and making it easy for anyone to use. The purpose is to reduce the test time.

Means for Solving the Problems The following describes the structure of the present invention. Silver bromide on the surface of photographic paper is completely removed using a photographic fixer, and the printed paper, which has been washed and dried, is soaked in water in advance. Wet it with sodium oxide solution.

After attaching this to the surface of the steel test piece to be tested and allowing the lead to react, the printed paper was removed and immersed in a sodium sulfide solution, causing the lead to appear as brown spots on the printed paper. 1. Printed paper moistened with a sodium hydroxide solution is pasted on the test surface of a working steel test piece, which allows the distribution of lead particles to be detected macroscopically. After a minute, the lead grains in the steel react with the sodium hydroxide on the printed paper, and by removing the printed paper and immersing it in a sodium sulfide solution, the reactive parts of lead appear as brown spots on the printed paper. come. The reaction in this case is thought to proceed according to the following equation.

Pb+NaOH+-120-+Na) IPb02+H
2iNaHPbOz +Na 28 +H20-+ P
bS + 3NaOH Therefore, the distribution of lead can be known macroscopically from the brown spots that appear on the printed paper.

Example Next, more specific examples will be described.

The steel lead print test method of the present invention is carried out by the following procedure.

(1) Preparation of test piece: As a general rule, the surface of the steel test piece to be tested is polished with emery paper lυθ~tsuθθ to remove dirt such as oil and fat.

(2) Preparation of print paper: As a general rule, general photographic paper (semi-gloss smooth surface) is thoroughly immersed in photographic fixer to completely remove silver bromide on the surface of the photographic paper, and then I Use the one that has been washed with water and dried.

(3) Lead print: The print paper prepared as described above is immersed in a 5% sodium hydroxide solution, and then attached and brought into close contact with the surface of the test piece. After applying for about 3 minutes, remove the printed paper from the test piece and sulfurize it by 5%) When immersed in IJium, the reactive area of lead appears on the printed paper as brown spots, and the dispersed state of the lead particles can be clearly identified. It can be done.

Effect of the invention The advantages of the present invention are as follows.

In other words, the work is easier than before because there is no need to corrode the surface of the sample to be inspected, and good prints can be obtained that clearly identify the distribution of lead particles regardless of the level of technical skill. Anyone can easily do this, such as omitting the process and simplifying the production of printed paper, and the total test time can be shortened, resulting in major effects in terms of technology and labor savings.

Source: Nakayama Steel Works Co., Ltd. □, -1:

Claims (1)

[Claims] 1. Completely remove silver bromide from the surface of photographic paper, wash and dry the paper, soak it in a sodium hydroxide solution, and apply this to the surface of the steel to be inspected (which has not been pretreated for corrosion, etc.). The distribution of lead particles in the steel is investigated by placing the printed paper in close contact with the steel (cross section) and reacting with lead, and then soaking the printed paper in a sodium sulfide solution to make the lead particles appear as brown spots. Lead print test method.