GB/T 39974-2021Magnesium partially stabilized zirconia ceramic element for oxygen measurement in molten steel (English PDF)

3.1 General requirements

The components shall be manufactured in accordance with the drawings and technical documents approved by the prescribed procedures, and shall meet the requirements of this standard.

3.2 Operating temperature range

The operating temperature range of the component. 1500°C~1750°C.

3.3 Appearance quality and dimensional accuracy

The appearance of the component is not allowed to have visible cracks; the size of the crack is less than 0.5mm, and each product cannot have more than two cracks.

The inner diameter, outer diameter, height, roundness and straightness of the components are in accordance with the requirements of the customer's drawings.

3.4 Component physical and chemical properties

The physical and chemical performance requirements of component materials are shown in Table 1.

3.5 Thermal shock resistance

After the component was subjected to five air-cooled thermal shock cycles from 1000°C (heat preservation 20min) to room temperature, there was no crack on the surface of the component visually.

4.1 General test conditions

According to the provisions of 4.1 in QC/T 413-2002.

4.2 Appearance quality and dimensional accuracy

The appearance quality of the components is inspected by visual inspection. Use accurate measuring tools to directly measure the dimensional accuracy and form tolerance of the product.

4.3 Element content

4.3.1 Determination of (ZrO2 HfO2 MgO) content

Determine the content of (ZrO2 HfO2) in accordance with YS/T 568.1-2008, and determine the content of MgO in accordance with HG/T 2573, and finally Add the two to determine the content of (ZrO2 HfO2 MgO).

4.3.2 Determination of Fe2O3 content

Determined according to YS/T 568.2-2008 regulations.

4.3.3 Determination of Na2O content

Determined according to YS/T 568.5-2008 regulations.

4.4 Determination of bulk density and apparent porosity

Using the same raw materials as the actual production products, the same molding and sintering process are used to prepare furnace samples, which are measured in accordance with GB/T 25995.

4.5 Conductivity

The samples are prepared using the same raw materials as the actual products, the same molding and sintering process, and the platinum slurry is used to prepare the electrodes during the test.

GB/T 5594.5 stipulates determination.

4.6 Thermal shock resistance

The element was subjected to 10 air-cooled thermal shock cycles from 1000°C (heat preservation 20min) to room temperature. After repeated 5 times, the surface of the sample was visually inspected. crack.

5.1 Factory inspection

The factory inspection items are appearance quality, dimensional accuracy, density, apparent porosity and electrical conductivity.

5.2 Type inspection

All items specified in Chapter 3 are type inspection items. Type inspection will be carried out when one of the following situations occurs.

a) Trial type inspection of new products or old products produced in different places.

b) After the formal production, if the structure, material, and process have major changes that may affect the performance of the product.

c) When the product has been stopped for more than 1 year and resumed production.

d) When there is a big difference between the factory inspection result and the last type inspection result.

e) When the national quality supervision agency requests for type inspection.

5.3 Sampling rules

5.3.1 Batch

A batch of products should be a group of product structures that are continuously produced by the same batch of raw materials on the same production line through the same process and submitted for acceptance at the same time.

If 200 pieces are used as a batch, it can still be used as a batch if there are less than 200 pieces.

5.3.2 Sampling

Each batch of components shall be checked and accepted according to the provisions of GB/T 2828.1. This standard recommends the use of.

---General inspection level. II;

---Reception quality limit. AQL0.40-AQL4.0;

---Sampling plan. a normal inspection sampling plan.

5.4 Judgment rules

When all inspection items meet the requirements specified in this standard, the batch of products is determined to be qualified. If there is an unqualified item, it should be from the same batch of products Double the number of products will be selected for re-inspection of unqualified items. When the re-inspection is qualified, the batch of products is still judged as qualified; if the re-inspection is still unqualified, then Determine that the batch of products is unqualified.