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Sintering furnace and method of making cutting tools

A cutting tool, sintering temperature technology, applied in the field of cutting tools, can solve the problems of expensive operation, unpredictable wear behavior, poor tolerance of workpiece surface, etc., to achieve the effect of reducing the size deviation from the nominal value

Active Publication Date: 2012-09-05
SANDVIK INTELLECTUAL PROPERTY AB
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Grinding operations after sintering are traditionally used to correct dimensional deviations, but this operation becomes increasingly expensive with the size of the defect
For tools that are directly sintered to final size and shape, so-called direct pressed cutting tools, deformation can cause positioning problems
An example is when directly pressed cutting tool inserts are mounted in tool holders, where dimensional imperfections can lead to unpredictable wear behavior and poor tolerances of the workpiece surface

Method used

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  • Sintering furnace and method of making cutting tools
  • Sintering furnace and method of making cutting tools
  • Sintering furnace and method of making cutting tools

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0033] By wet milling WC, Co, TaC and Ta 0.8 Nb 0.2 C to prepare a commercially available cemented carbide grade powder mixture with a nominal composition (wt%) of 11.50% Co, 81.61% W, 1.17% Ta, 0.28% Nb. The powder was spray dried and compacted into SNMM-15 compacted green bodies of square geometry with a nominal sintered side length of 15 mm. Powder properties and compaction cycles are selected to minimize powder density changes in the form, thereby reducing shape distortion caused by the powder and compaction process. After pressing, the compacted green body was placed on a circular sintering tray with a diameter of 290 mm according to usual procedures. About 72 compacted green bodies are placed on each sintering tray, see image 3 . No specific rotation or alignment of the compacted green bodies on the tray was used.

example 2

[0034] Example 2 (the present invention)

[0035] The pressed compacts of Example 1 were sintered in a vertical columnar furnace on a stack of a total of 50 sintering trays forming a height of 600 mm and a diameter of 290 mm. Tray material is isostatically pressed graphite. The cylindrical heating element of the furnace has a diameter of 430 mm, a height of 580 mm and a thickness of 15 mm. There are also heating elements at the top and bottom, both 15mm thick. Between the heating element and the stack of graphite trays there is a graphite retort whose top and bottom plates are closed throughout the process. The inner diameter of the cylindrical retort is 310 mm, the height is 580 mm, and the thickness is 7.5 mm. The thickness of the top and bottom plates of the retort was also 7.5 mm. The cylindrical insulation located outside the retort has an inner diameter of 540mm and a height of 1150mm. The thickness of the columnar insulating part is 40mm, while the thickness of t...

example 3

[0038] Example 3 (the present invention)

[0039] The pressed compacts of Example 1 were sintered in a vertical columnar furnace on a stack of a total of 50 sintering trays forming a height of 600 mm and a diameter of 290 mm. Tray material is isostatically pressed graphite. The cylindrical heating element of the furnace has a diameter of 430 mm, a height of 580 mm and a thickness of 15 mm. There are also heating elements at the top and bottom, both 15mm thick. Between the heating element and the stack of graphite trays there is a graphite retort whose top and bottom plates are closed throughout the process. The inner diameter of the cylindrical retort is 310 mm, the height is 580 mm, and the thickness is 7.5 mm. The thickness of the top and bottom plates of the retort was also 7.5mm. The cylindrical insulation located outside the retort has an inner diameter of 540mm and a height of 1150mm. The thickness of the columnar insulating part is 40mm, while the thickness of th...

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Abstract

The present invention relates to a method of making cutting tools comprising a substrate having a hard phase and a binder phase, the method comprising forming green powder compacts using powder metallurgical techniques, charging the green powder compacts, placed on one or several trays, in a furnace and sintering the green powder compacts wherein the furnace comprises an insulation package (9), at least three individually controlled heating elements located inside the insulation package (9) including a vertical heating element (5), an upper horizontal heating element (6) arranged in an upper part of the furnace, and a lower horizontal heating element (7) arranged in a lower part of the furnace, wherein operating the at least three heating elements such that an average controlled cooling rate from a sintering temperature down to at least a solidification temperature of the binder phase is 0.1-4.0 DEG C / min, and a sintering furnace operable to obtain a controlled cooling rate.

Description

technical field [0001] The present invention relates to a method of manufacturing cutting tools for machining operations such as milling, drilling and turning. Background technique [0002] Tungsten carbide-based alloys, commonly known as cemented carbides, are used in a wide range of applications; most importantly as a material for cutting tools. In this application, the alloy typically includes a cobalt binder phase, and typically may contain minor amounts of one or more of the Group IVa, Va, and VIa elements. Another important material group for cutting tool applications are alloys based on titanium carbonitride, commonly known as cermets. They usually contain a metallic binder phase of cobalt and / or nickel and contain, most commonly, carbides and / or nitrides of one or more group IVa, Va and VIa elements. [0003] Substrates for cutting tools, such as cemented carbide or cermets, are produced using powder metallurgy methods. Typically this involves mixing / milling the b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/10C22C29/02C22C29/08F27B1/26
CPCB22F2999/00B22F3/003F27B17/00B22F2005/001B22F3/1028F27B5/14B22F2203/11F27D21/0014
Inventor 安德斯·卡尔森古尼拉·安德森彼得·比约克哈根佩尔·古斯塔夫松马尔科·兹温克尔斯
Owner SANDVIK INTELLECTUAL PROPERTY AB