SU722995A1 - Paste for parts protecting against cementation - Google Patents

Description

one

The invention relates to the metallurgy of cemented structural steels and can be used in the chemical-heat treatment of steel parts and is intended to protect against carburization of individual surfaces of parts during cementation.

A known carburizing protection paste during carburization consisting of a mixture of refractory metal oxides, borax and talc, containing, in wt.%:

Nickel oxide 2O

Dehydrated Borax 55

Talc10

Ethyl alcohol 15 1.}.

A paste is also known, consisting of 2 parts of talc, one part of white goose and one part of water with the addition of liquid glass to a creamy consistency 2.

However, these pastes do not provide reliable protection against carburization during gas cementation of mechanically untreated, after hot stamping, surfaces of low strength, porosity, and heterogeneity in coating composition. There were cases of point breakdowns and carbonaceous stains.

The aim of the invention is to create such an anti-cemention paste that would provide reliable protection against carburization during cementation in a gaseous medium and in a solid carburizer, both machined and surfaces of parts after 1 hour of stamping.

The goal is achieved by the fact that the paste based on talc and kaolin is known, additionally contains dehydrated borax, marchalite and alumina with the following ingredients, wt%:

Kaolin 4-10

Talc8-14

Marchalit2,5-4,0

Borax dehydrated 0, 3-1,2

0.2-0.8

Aluminum Oxide Liquid Glass

The flesh of such a paste is 1,., 8 g / cm. The proposed paste for applying it to protects the previously degreased surface of the part with a hot aqueous solution of soda and drying the coating at a temperature of 50-80 ° C provides a durable, uniform in composition, non-porous, uniform, which reliably prevents machined as well as mechanically untreated surfaces of parts after hot stamping from saturation with carbon. Method of application: dipping or applying the paste on the protected surfaces of parts with a brush, followed by drying at a temperature of SO-SO C.

The composition of the paste, wt.%

Example. The silt on the surface of the parts (lp, bits) is applied by dipping the compositions No. 1-5. Carry out gas grouting and grouting in a carburizer (charcoal and semi-coke) to a depth of 1.7-2.5 mm gph temperature; e. 940 + 10 ° C. After treatment in protected areas with a hollow, there is no saturation with carbon.

Using the proposed paste as

anti-cementation coating provides guaranteed protection against carbon saturation Steel surfaces that are not subject to cementation, which is due to

Increase tool performance (bits) in penetration by 7%, in terms of mechanical speed by iO%,

The table shows rzzulbtaty 5: The compositions of pastes.

Claims (2)

Claim A paste for protecting parts from cementation, containing kaolin and talcum, about τα and repetitive in that, in order to increase the reliability of protection of parts during processing, it additionally contains marshalite, borax dehydrated, aluminum oxide and water glass in the following ratio of components, wt.% : Kaolin 4-10 Talcum powder 8-14 50 Marshall 2.5-4.0 40 Borax is dehydrated - naya 0.3-1.2 Alumina 0.2-0.8 Liquid glass 70-85 45 Sources of information taken into account in the examination 1. German patent No. 1286869, 48 V 11/10, published. 1964. 2. Directory of metalworker. Mashgiz, 1959, p. 253.