CN101209491A

CN101209491A - Method for casting printing machine as-cast nodular iron roller body

Info

Publication number: CN101209491A
Application number: CNA2006101478887A
Authority: CN
Inventors: 徐清
Original assignee: HUAXIN ALLOY CO Ltd SHANGHAI
Current assignee: HUAXIN ALLOY CO Ltd SHANGHAI
Priority date: 2006-12-25
Filing date: 2006-12-25
Publication date: 2008-07-02
Anticipated expiration: 2026-12-25
Also published as: CN100586608C

Abstract

The invention discloses a casting method of a cast nodular iron roller cylinder of a printing machine. The steps of the method comprise sand mixture modeling, mould assembling, burden melting, inoculation tapping, casting, cooling, unpacking, casting cleaning, quality inspecting, casting rough machining and artificial aging. The method is characterized in that: the burden melting step comprises burden arranging and melting, and the burden comprises 40 to 60wt percent of pig iron, 30 to 40wt percent of foundry return, and 10 to 30wt percent of scrap steel; iron liquor melting is done to the arranged burden by adopting an intermediate frequency induction electric furnace, and the highest melting temperature is 1530 to 1540 DEG C; the inoculation tapping step comprises two steps of spheroidisation and barium ferrosilicon first inoculation; a secondary inoculation processing is done at the same time with the casting step.

Description

Method for casting printing machine as-cast nodular iron roller body

Technical field

The present invention relates to a kind of casting method, particularly a kind of method for casting printing machine as-cast nodular iron roller body.

Background technology

The printer roller cylindrical shell is the key components and parts of decision and restriction press speed and effect.Along with the raising of printing technology, print speed printing speed by original per hour 8000 bring up to 13000.After the printing machine speed-raising, the mechanical performance of roller body is had higher requirement, mouthful foundry goods HT250 trade mark of ash does not originally satisfy requirement.New printer roller cylinder material will satisfy tensile strength 〉=500Mp, percentage elongation 〉=7%, hardness HBS=170～230; Metallographic structure requires nodularization rate 〉=80% at roller body working face 31mm thickness place, and content of pearlite in alloy is 5～30%; Roller body working face wall thickness is wanted evenly, and wall thickness deviation≤1mm is steadily moving to guarantee product; Not allowing casting iron defect on the roller body working face exists.Therefore how to satisfy the key that above-mentioned specification requirement has become casting printer roller cylindrical shell.

Summary of the invention

Technical problem to be solved by this invention provides a kind of method for casting printing machine as-cast nodular iron roller body, so that the printing machine as-cast nodular iron roller body of producing can satisfy the requirement of printing speed-raising back to printing machine as-cast nodular iron roller body, the technical scheme that it adopts is:

A kind of method for casting printing machine as-cast nodular iron roller body, its step comprise mixed husky moulding, mould assembly, and the furnace charge melting is bred and tapped a blast furnace, cast, and cooling, unpacking, casting cleaning, quality inspection, foundry goods roughing, artificial aging is characterized in that:

Described furnace charge melting step comprises configuration furnace charge and melting, and the weight proportion of furnace charge is: contain the pig iron of 40-50%, the foundry return of 30-40%, the steel scrap of 10-30%; Institute's furnace burdening adopts medium-frequency induction furnace to carry out the melting of iron liquid, and maximum temperature is 1530-1540 ℃ during fusing; The described ironworker's of being pregnant with preface comprises that spheroidising and silicon barium once breed two steps, and will carry out simultaneously handling with stream sulphur oxygen late inoculation in the cast operation.

Wherein, the total amount of the nodulizer that described spheroidising step adds is the 1.5%-1.6% of the melting amount of tapping a blast furnace, and the nodulizer granularity is 4～20mm, and the chemical composition mass percent of nodulizer is: the Mg of 5.9-6.3%, the RE of 2.0-2.4%, the Si of 44-48%, the Ca of 2.1-2.5% is less than or equal to 1.0% Al, and the Fe of surplus, add this nodulizer, if breed proper, spheroidizing that can fine performance magnesium and rare earth to desulfurization, degas and in and the harmful element good effectiveness.

The granularity of the silicon titanate innoculant that inoculation step of described silicon barium is selected is 5-10mm, the total amount of the silicon titanate innoculant that adds is the 0.5%-0.6% of the melting amount of tapping a blast furnace, the chemical composition mass percent of silicon titanate innoculant is: the Si of 60-70%, the Ca of 0.8-2.2%, be less than or equal to 1.0% Al, the Ba of 4.0-6.0%, and the Fe of surplus, inoculation is the key of ductile iron production, large-section magnesium iron is even more important, pregnant effect has determined the quantity of graphite nodule, the size of graphite nodule and the roundness of graphite nodule, this of adding kind of silicon titanate innoculant can effectively increase the quantity of graphite nodule and have the anti-ageing ability of moving back.

The granularity with the sulphur oxygen inovulant in the processing of stream sulphur oxygen late inoculation of carrying out simultaneously in cast is 0.2-0.7mm, the total amount of the sulphur oxygen inovulant that adds is the 0.1%-0.15% of the melting amount of tapping a blast furnace, the chemical composition mass percent of sulphur oxygen inovulant is: the Si of 70-76%, the Ca of 1.5-2.0%, the Al of 0.75-1.25%, the Ce of 1.5-2.0%, the S of 0.5-0.8%, the O of 0.3-0.5%, and the Fe of surplus, handle through late inoculation so again, guaranteed nodularization rate and nodularization quality more.

Before the mould assembly, be provided with floamed ceramics filtrating piece in described mixed husky moulding, the mould assembly operation in the sprue bottom; Described cast program adopts upright cast rising pouring pouring technology, and wherein pouring temperature is controlled at 1380-1400 ℃.

The invention has the beneficial effects as follows:

After adopting casting method of the present invention, the printer roller cylindrical shell tensile strength 〉=500Mp that produces, percentage elongation 〉=7%, hardness HBS=170～230; The nodularization rate at metallographic structure roller body working face 31mm thickness place is greater than 80%, content of pearlite in alloy is 5～30%, and roller body working face wall thickness is wanted evenly, wall thickness deviation≤1mm, do not have casting iron defect to exist on the roller body working face, satisfy of the requirement of printing speed-raising back fully the printer roller cylindrical shell.

The specific embodiment

Embodiment 1, and method for casting printing machine as-cast nodular iron roller body comprises:

(1) mixes husky moulding, mould assembly

Adopt the horizontal moulding of furane self-hardening sand molding then, repair type, coat, core down, in the sprue bottom floamed ceramics filtrating piece is set, mould assembly then, to be cast with behind the tight case of bolt casting mold being holded up etc.

(2) furnace charge melting

Dispose furnace charge earlier, the weight proportion of furnace charge is: contain 40% the pig iron, 40% foundry return, 20% steel scrap; Then the furnace charge that configures is dropped into medium-frequency induction furnace and carry out the melting of iron liquid, maximum temperature is 1540 ℃ during fusing, leaves standstill insulation 5～10 minutes, allows impurity in the iron liquid is fully floating to come up, claw with the rapid collection of rapid slag agent, do not allow these impurity bands in the iron liquid of handling.

(3) breed and tap a blast furnace

Specifically comprise two steps of inoculation of spheroidising and silicon barium, wherein spheroidising is adopted and is poured the method spheriodization process thereof, the nodulizer granularity is 4mm, the nodulizer addition is 1.5% of the melting amount of tapping a blast furnace, iron liquid tapping temperature is 1460～1490 ℃, the amount of tapping a blast furnace is 2/3 of a total amount for the first time, the spheroidizing reacion time is 60～90 seconds behind the adding nodulizer, after finishing, takes off question response the scum silica frost on the quiet iron liquid, add again into remaining 1/3 iron liquid, at this moment carry out inoculation one time along with iron liquid stream adds silicon titanate innoculant; The chemical composition mass percent of nodulizer is: 5.9% Mg, 2.0% RE, 48% Si, 2.1% Ca, 1.0% Al, and the Fe of surplus; The granularity of the silicon titanate innoculant that adds is 5mm, and the total amount of the silicon titanate innoculant of adding is 0.5% of the melting amount of tapping a blast furnace, and the chemical composition mass percent of silicon titanate innoculant is: 70% Si, 2.2% Ca, 1.0% Al, 4.0% Ba, and the Fe of surplus.

(4) cast

Adopt vertical upright casting rising pouring pouring technology, in the sprue bottom floamed ceramics filtrating piece is set and carries out pushing off the slag; Wherein pouring temperature is controlled at 1400 ℃; Cast adds sulphur oxygen inovulant with stream simultaneously and carries out late inoculation, wherein the granularity of sulphur oxygen inovulant is 0.2mm, the total amount of the sulphur oxygen inovulant that adds is 0.1% of the melting amount of tapping a blast furnace, the chemical composition mass percent of sulphur oxygen inovulant is: 76% Si, 2.0% Ca, 0.75% Al, 2.0% Ce, 0.8% S, 0.5% O, and the Fe of surplus.

(5) cooling, unpacking

(6) casting cleaning

(7) quality inspection

Quality inspection, underproof eliminate, the qualified subsequent processing that enters.

(8) foundry goods roughing

(9) artificial aging

Take artificial aging to handle by technological requirement, eliminate stress.

Following table 1 is the main technologic parameters of several embodiments of the present invention.

Table 1

The technical process of embodiment 2,3,4 repeats no more with embodiment 1.

Claims

1. method for casting printing machine as-cast nodular iron roller body, its step comprise and mix husky moulding, mould assembly, and the furnace charge melting is bred and tapped a blast furnace, and cast, is unpacked casting cleaning, quality inspection, foundry goods roughing, artificial aging at cooling; It is characterized in that:

Described furnace charge melting step comprises configuration furnace charge and melting, and the weight proportion of furnace charge is: contain the pig iron of 40-50%, the foundry return of 30-40%, the steel scrap of 10-30%; Institute's furnace burdening adopts medium-frequency induction furnace to carry out the melting of iron liquid, and maximum temperature is 1530-1540 ℃ during fusing; The described ironworker's of being pregnant with preface comprises that spheroidising and silicon barium once breed two steps; And to carry out simultaneously handling with stream sulphur oxygen late inoculation in the cast operation.

2. method for casting printing machine as-cast nodular iron roller body as claimed in claim 1, it is characterized in that: the total amount of the nodulizer that described spheroidising step adds is the 1.5%-1.6% of the melting amount of tapping a blast furnace, the chemical composition mass percent of nodulizer is: Mg 5.9-6.3%, RE 2.0-2.4%, Si 44-48%, Ca 2.1-2.5%, Al≤1.0%, surplus is Fe.

3. method for casting printing machine as-cast nodular iron roller body as claimed in claim 2 is characterized in that: described nodulizer granularity is 4～20mm.

4. method for casting printing machine as-cast nodular iron roller body as claimed in claim 1, it is characterized in that: inoculation step of described silicon barium, the total amount of the silicon titanate innoculant that adds is the 0.5%-0.6% of the melting amount of tapping a blast furnace, the chemical composition mass percent of silicon titanate innoculant is: the Si of 60-70%, the Ca of 0.8-2.2%, be less than or equal to 1.0% Al, the Ba of 4.0-6.0%, and surplus is Fe.

5. method for casting printing machine as-cast nodular iron roller body as claimed in claim 4 is characterized in that: the granularity of described silicon titanate innoculant is 5-10mm.

6. method for casting printing machine as-cast nodular iron roller body as claimed in claim 1, it is characterized in that: the total amount of the sulphur oxygen inovulant that adds in cast is carried out with the processing of stream sulphur oxygen late inoculation simultaneously is the 0.1%-0.15% of the melting amount of tapping a blast furnace, the chemical composition mass percent of sulphur oxygen inovulant is: Si 70-76%, Ca 1.5-2.0%, Al 0.75-1.25%, Ce 1.5-2.0%, S 0.5-0.8%, O 0.3-0.5%, surplus is Fe.

7. method for casting printing machine as-cast nodular iron roller body as claimed in claim 6 is characterized in that: the granularity of described sulphur oxygen inovulant is 0.2-0.7mm.

8. method for casting printing machine as-cast nodular iron roller body as claimed in claim 1 is characterized in that: before the mould assembly, be provided with floamed ceramics filtrating piece in the sprue bottom in described mixed husky moulding, the mould assembly operation.

9. method for casting printing machine as-cast nodular iron roller body as claimed in claim 1 is characterized in that: described cast program adopts upright cast rising pouring pouring technology, and wherein pouring temperature is controlled at 1380-1400 ℃.