Isothermal quench bainitic ductile cast iron and use thereof

A bainitic nodular graphite and austempering technology, applied in the field of bainitic nodular cast iron, can solve problems such as difficult popularization and application, high cost, and short service life, and achieve huge economic benefits, low cost, and long service life.

Inactive Publication Date: 2009-01-21
朱志文
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The materials currently used are not difficult to meet the needs of use, the serv

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: The composition weight ratio (wt%) of austempering bainitic ductile iron is: 3.50~3.8%C, 2.2~2.7%Si, 0.2~0.5%Mn,≤0.07%P,≤0.03%S, 0.03 ~0.06% Mg, 0.01~0.04% Re, 0.45~0.75% Cu, the balance is Fe. The as-cast structure of the austempering bainite ductile iron is: spheroidization rate 1-3, graphite ball diameter 5-7, pearlite content > 50%, phosphorus eutectic and cementite total ≤ 3%. The mechanical properties are: tensile б b At least 1000Mpa, yield б 0.2 At least 700Mpa, elongation δ is at least 5%, impact value a K At least 80J / cm 2 , the hardness is at least 300 ~ 360HB. In practical application, any value (including the end value) in the weight ratio of the above-mentioned components can be used for production.

[0016] During production, during the austempering process, the control of workpiece deformation is a relatively important link. It can be solved by changing the furnace loading method during heating. Tempering is beneficial to obtain a tempe...

Embodiment 2

[0018] In this embodiment, the austempering bainite ductile iron is used as pump fittings. Pump accessories include at least a pump body and an impeller. The rest are similar to Embodiment 1, and will not be repeated here.

[0019] Generally, the weight of the pump body of a mining pump reaches 110kg after rough machining, and the wall thickness is very uneven (45mm at the thick wall and only 15mm at the thin wall). It is very difficult to achieve the uniformity of mechanical properties and hardness. . Adopt the following heat treatment process: preheating, heat preservation, quenching (starting quenching), successfully produced a qualified lower bainite ductile iron pump body, and the hardness difference is controlled within the range of HB50 (HB280-290 at the thick wall, HB320 at the thin wall) ~330, test bar HB330) mechanical properties also meet the technical requirements.

Embodiment 3

[0021] In this embodiment, the austempering bainite ductile iron is used as an accessory of a wire drawing machine. Drawing machine accessories include at least pulleys. The target value of heat treatment for wire drawing machine parts is to obtain a stable upper bainite structure, in which the length of lower bainite is 1 to 3 grades, the number of white areas is 1 to 2 grades, and the number of ferrite is 1 to 2 grades (JB3021-81). Ensure that the workpiece reaches the required mechanical properties after heat treatment. The above problems can be solved by formulating a reasonable heating temperature and heat preservation process during austenitization, as well as a process for isothermal treatment temperature and isothermal time. Austenitizing is carried out in an electric box furnace with a protective atmosphere. The isothermal treatment is carried out in a salt bath furnace with cooling circulating water pipeline and compressed air stirring, using nitrate prepared from ...

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Abstract

The invention relates to an austempering bainite spheroidal graphite cast iron and application thereof. The compositions by weight percent of the austempering bainite spheroidal graphite cast iron are 3.50 to 3.8 percent of carbon, 2.2 to 2.7 percent of silicon, 0.2 to 0.5 percent of manganese, less than or equal to 0.07 percent of phosphor, less than or equal to 0.03 percent of sulfur, 0.03 to 0.06 percent of magnesium, 0.01 to 0.04 percent of rhenium, 0.45 to 0.75 percent of copper, and the balance being iron. The austempering bainite spheroidal graphite cast iron is used as a fitting part of a pump or a fitting part of a pulling machine. The austempering bainite spheroidal graphite cast iron has the advantages that: firstly, the austempering bainite spheroidal graphite cast iron has superior comprehensive performance, is easy to manufacture and has low cost; secondly, the austempering bainite spheroidal graphite cast iron has long service life, low manufacturing cost, superior corrosion resistance and abrasion resistance, and good strength, plasticity and toughness; and thirdly, the industrial production of the austempering bainite spheroidal graphite cast iron on pump products, particularly the application of the austempering bainite spheroidal graphite cast iron on marine pump products and mine pump products and the application of the austempering bainite spheroidal graphite cast iron as the fitting part of the pulling machine effectively improve the product performance in the two industries and can bring about significant economic benefit.

Description

technical field [0001] The invention relates to the field of bainitic ductile iron, in particular to the field of austempering bainitic nodular cast iron and its application. The austempering bainitic nodular cast iron is especially suitable for pump accessories and wire drawing machine accessories. Background technique [0002] Austempered bainitic ductile iron (Austempered Ductile Iron referred to as ADI) is a new type of metal material with excellent comprehensive properties. It has both high strength and high plastic toughness, and has high wear resistance, impact resistance and good corrosion resistance. Its application in appropriate fields can effectively prolong the service life of products and reduce costs. In the 1970s and 1980s, a few countries in the world, including Finland and China, carried out research and development on this. With in-depth research and application, this material has attracted great interest and great attention from experts in the field of e...

Claims

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Application Information

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IPC IPC(8): C22C37/10
Inventor 朱志文
Owner 朱志文
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