CN102330011A - Production method of high-strength high-toughness nodular iron crankshaft without adding ferroalloy or isothermally quenching - Google Patents

Abstract

The invention relates to a production method of a high-strength high-toughness nodular iron crankshaft without adding ferroalloy or isothermally quenching. The method comprises the following steps: (1) selecting the following components in percentage by weight: 55 to 60 percent of high-quality Q10 pig iron, 12 to 15 percent of CrMo or CrMoCu-containing scrap steel, and the balance of nodular iron foundry return; and (2) melting according to a normal melting process of perlitic cast nodular iron, and performing melting inoculation treatment and spheroidisation, wherein the content of perlitic cast is 85 percent, nodularization degree is between 1 and 2 grade, graphite is between 6 and 7 grade, and the nodular iron crankshaft is required to comprise the following components in percentage: 0.1 percent of Cr, 0.04 to 0.05 percent of Mo, 3.72 to 3.78 percent of C, 2 to 2.5 percent of Si, and 0.45 to 0.5 percent of Mn. According to the production method, the scrap steel and the nodular iron foundry return are recycled, so that the resources are saved, the production cost of an enterprise is reduced, the produced nodular iron crankshaft has high strength and high toughness, and the economical benefit of the enterprise is improved.

Description

Do not add iron alloy, not isothermal quenching production HS, high-toughness ductile iron bent axle method

Technical field

The invention belongs to the spherulitic iron crankshaft working method, be specifically related to a kind of iron alloy, not isothermal quenching production HS, high-toughness ductile iron bent axle method of not adding.

Background technology

HS oil engine pearlitic ductile iron bent axle, tensile strength reaches as high as 1000Mpa, can only reach below 3% but unit elongation is the highest.Because its toughness is relatively poor, can only be used on the medium and small displacement internal combustion machine.In order to realize that on heavy duty truck and medium-sized boats and ships toughness that casting and forging just must manage to improve spherulitic iron crankshaft.The method that improves spherulitic iron crankshaft has two kinds at present: a kind of is to add iron alloy cast alloy spherulitic iron crankshaft, and another kind is that Bei Shi spherulitic iron crankshaft difficult to understand is produced in isothermal quenching, but these two kinds of method production costs are high.End products such as present automobile agricultural machinery all in price reduction, also only fall and do not rise by the bent axle price, and the pig iron etc. are cast the also significantly rise in price especially of raw and auxiliary material, electricity, oil, interest, wage, so the bent axle product has faced the loss edge, obviously use these two kinds of methods all inadvisable.

Summary of the invention

Technical problem to be solved by this invention is to overcome above-mentioned deficiency, and a kind of iron alloy, not isothermal quenching production HS, high-toughness ductile iron bent axle method of not adding is provided, and this method does not increase cost, and the spherulitic iron crankshaft intensity of producing is high, toughness is high.

Technical scheme of the present invention: a kind of iron alloy, not isothermal quenching production HS, high-toughness ductile iron bent axle method of not adding, it may further comprise the steps:

(1) selecting content for use is the high-quality Q10 pig iron 55～60% of gross weight, and the steel scrap content that cooperates CrMo or contain CrMoCu is 12～15% of gross weight, and all the other are the magnesium iron foundry return;

(2) press the melting of pearlitic ductile iron normal smelting technology, melting inoculation and spheroidizing, final content of pearlite in alloy 85%; The nodularization I and II, 6～7 grades in graphite requires spherulitic iron crankshaft finally to contain Cr:0.1%; Mo:0.04～0.05%; C:3.72～3.78%, S i:2～2.5%, Mn:0.45～0.5%.

The present invention compared with prior art has following beneficial effect: the present invention utilizes steel scrap and magnesium iron foundry return again, the resource of not only practicing thrift, and reduced the enterprise production cost, the spherulitic iron crankshaft intensity of production is high, the toughness degree, has improved economic benefit of enterprises.

Embodiment

Embodiment 1

Produce QT800-6 HS, high-toughness ductile iron bent axle, the first step is selected the high-quality Q10 pig iron for use, and content is 55% of gross weight, and joining the steel scrap content that contains CrMo is 15% of gross weight, and magnesium iron foundry return content is 30% of gross weight; In second step, press the melting of pearlitic ductile iron normal smelting technology, melting inoculation and spheroidizing; Final content of pearlite in alloy 85%, nodularization I and II, 6～7 grades in graphite; Require spherulitic iron crankshaft finally to contain Cr:0.1%, Mo:0.04～0.05%, C:3.72～3.78; S i:2～2.5%, Mn:0.45～0.5%.

Embodiment 2

Produce QT800-6 HS, high-toughness ductile iron bent axle, the first step is selected the high-quality Q10 pig iron for use, and content is 60% of gross weight, and joining the steel scrap content that contains CrMo is 20% of gross weight, and magnesium iron foundry return content is 20% of gross weight; In second step, press the melting of pearlitic ductile iron normal smelting technology, melting inoculation and spheroidizing; Final content of pearlite in alloy 85%, nodularization I and II, 6～7 grades in graphite; Require spherulitic iron crankshaft finally to contain Cr:0.1%, Mo:0.04～0.05%, C:3.72～3.78; S i:2～2.5%, Mn:0.45～0.5%.

Embodiment 3

Produce QT900-5 HS, high-toughness ductile iron bent axle, the first step is selected the high-quality Q10 pig iron for use, and content is 58% of gross weight, and the steel scrap content that contains CrMoCu is 17% of gross weight, and magnesium iron foundry return content is 25% of gross weight; In second step, press the melting of pearlitic ductile iron normal smelting technology, melting inoculation and spheroidizing; Final content of pearlite in alloy 85%, nodularization I and II, 6～7 grades in graphite; Require spherulitic iron crankshaft finally to contain Cr:0.1%, Mo:0.04～0.05%, C:3.72～3.78; S i:2～2.5%, Mn:0.45～0.5%.

Claims (1)

1. one kind does not add iron alloy, not isothermal quenching production HS, high-toughness ductile iron bent axle method, it is characterized in that it may further comprise the steps:

(1) selecting content for use is the high-quality Q10 pig iron 55～60% of gross weight, and joining the steel scrap content that contains CrMo or contain CrMoCu is 12～15% of gross weight, and all the other are the magnesium iron foundry return;

(2) press the melting of pearlitic ductile iron normal smelting technology, melting inoculation and spheroidizing, final content of pearlite in alloy 85%; The nodularization I and II, 6～7 grades in graphite requires spherulitic iron crankshaft finally to contain Cr:0.1%; Mo:0.04～0.05%; C:3.72～3.78%, S i:2～2.5%, Mn:0.45～0.5%.