CZ544190A3 - Knife for meat disintegrating and mixing machines - Google Patents

Abstract

Martensitic Cr steel contg. (wt. %) 0.7-0.9C, less than 1 Si, less than 1 Mn, 0.5-1.5 Mo, 0.7-0.95 V, 0.3-0.9 Nb, 12.1-13.9 gcr, remainder Fe is used for cutting knives for cutting meat. A partic. advantageous steel contains 0.80C, 0.50 Si, 0.45 Mn, 13.0 Cr, 1-3 Mo, 0.90V, and 0.70 Nb. Corrosion resistance is improved by rotatably high Mo content and grain-refining effect of Nb, while Nb carbides and secondary carbides give near resistance. ADVANTAGE - Optimum properties at formable cost.

Description

The invention relates to the use of martensitic chromium steel, which is high-strength, tough and corrosion-resistant, for the production of knives for meat grinding and mixing machines.

>: Such knives are mainly used for slicing meat. Steel suitable for such knives must have a certain range of properties. Such a spectrum includes, on the one hand, corrosion resistance against tissue fluids, essentially saline solutions that result from slicing meat, on the other hand high hardness to ensure blade durability, and high strength to withstand centrifugal forces at high rotational speeds of around 4000 rpm, abrasion resistance in order to achieve large time intervals between grinding. On the one hand, satisfactory toughness, so that it is also possible to slice harder, for example deep-frozen pieces, is one of the polishes of the st. It should also be possible to manufacture them with as low a cost as possible. . and..·'. . . . . . , _

S * tf * tZ 92-23 1 51 7 94 It has long been known to use martensitic corrosion for such knives

thunder steel with 9.2 to 2.5 .:. t / Vk c krouu 5.:.:0 .: also usual phosphorus, sulfur and nitrogen, ia ·

¹ / - km Jtfcm molybdenum 3 /: 12) 3 tungsten. An example is a steel with about 4 wt / wt of 3.5 wt% ^per kilometer of acanane and 0.2 wt ^/ wt of silicon, 13 wt / wt. chromium, 1. molybdenum and 0.14 mol / L nitrogen. Similarly, composite steels for cutting tools with additional carbide-forming elements, such as vanadium, titanium, tantalum, niobium and zirconium, in a total amount of up to 2 manganese, are known from DE-A3 17 52 355. An example is 0.3 wt% of carbon, 1 wt% of silicon,

0.33 wt.% Manganese, 10.5 wt.% Chromium and 1 molybdenum. The known steel contains at least 20 wt.% of austenite.

(Special use for knives for meat grinding and mixing machines is known from 02-03 33 30 1, irradiating steel, in which either a hard medium layer is provided between two tough layers or a tough middle layer. For the individual layers, steels with a relatively high chromium content are used, for example with 14 or more flame-retardant chromium _. It has a low carbon content of about 0.1% w / w.

?. :) obsa ^ iu <r -: iL ku n?; an: ar.v. After this, the percentage of wetness of these steels will be 1 to 2% by weight of molybdenum and 1 to 2% by weight of vanadium.

in? /the. SUMMARY OF THE INVENTION It is an object of the present invention to provide a steel for knives for meat grinding and mixing machines which, in view of the aforementioned spectrum of properties, is of optimum value at favorable production costs.

According to the invention, this object is achieved by a martensitic steel consisting of

0.7 to 0.3 EOfUÍé carbon, less No ž 1 mass 7c silicon, less than 1 hmo here X Manganese, V j 3 and z l, o hm o t !. : <· molvbdenu 3.7 to 0.95 over here vanadium, 0.3 to 0, 3 7 niobium,

12.1 to 13.3 wt.% Of chromium, the remainder being iron, including impurities below the molten metal.

eject in -h.h '’‘ -The steel from this area is about · <0, .. 80 haoSux carbon, 0.50 h.totiu # silicon, 0.45 hmoíAát

Manganese, 13% by weight of chromium-1, 3% molybdenum, 3.90% by weight 14% vanadium and 0.70% by weight niobium have proven particularly useful for such knives. . This is due to the fact that the steel used according to the invention has a material number of 1.4153 as compared to the steel used hitherto because of its higher molybdenum content and the grain-refinement

corrosion resistance exerted by niobium, ilimoto, primary niobium carbides, excreted in fine form;

Tangent with secondary carbides eliminated during tempering ensure high abrasion resistance.

► ~ 1 ~~~ ^I Preparation of steel is carried out the usual melt-metallurgical route. Hot and subsequently cold rolled strips are processed into knives.

The blades are rapidly cooled after austenitization at 1050 to 1100 ° C to form a mantensitic web from the curing temperature and then tempered at 460 to 550 ° C for optimum hardness, toughness and corrosion resistance.

Thereafter, the properties listed below are achieved.

With roughly the same hardness according to the invention, the steel used, on account of its finer and more uniform carbide formation, achieves a 15 to 25% higher toughness, as can be seen from FIG. 1.

In long-term experiments, a permanent fatigue resistance of 50% was found to be higher by _t ' _t ΈοΤ' allow 'to significantly increase the resistance of highly stressed knives of this type. In the salt spray test, the steel according to the invention produced a significantly higher attack rate;

corrosion than comparable steel, material number

Claims (2)

PATENT CLAIMS % Of silicon, less than 1 wt. % manganese, 0.5 to 1.5 wt / v% molybdenum, 0.7 to 0.95 wt. % vanadium, 0.3 to 0.9 w / w, niobium, 12.1 to 13.9 w / w% chromium, the remainder being iron including melting impurities. 1. / Knife for meat grinding and mixing machines made of martensitic chromium steel, characterized in that it consists of 0.7 to 0.9% by weight of carbon, less than t Knife according to claim 1, characterized in that it consists of 0.80 masses. % carbon, 0.50 wt / wt. % silicon, 0.45 wt / 1% manganese, 13 wt. % chromium, 1.3 wt / l, molybdenum, 0.90 wt. % vanadium and 0.70 wt.% niobium, the remainder being iron.