阅读说明：本技术 一种内螺纹无缝钢管内模生产工艺 (A kind of internal-thread seamless steel pipe internal model production technology ) 是由 周益鑫 于 2019-09-17 设计创作，主要内容包括：本发明公开了一种内螺纹无缝钢管内模生产工艺,包括以下步骤：1)选材和外形加工；2)渗硼处理；3)加热处理；4)淬火；5)回火；6)空冷。本发明属于钢管生产模具加工技术领域,具体是提供了一种通过渗硼处理提高模具表面硬度高和耐磨性从而延长模具使用寿命、以高强度材料配合热处理淬火处理提高模具基体强度和韧性、使用保护气体对模具进行空冷避免表面裂纹和氧化层提高表面光洁度的内螺纹无缝钢管内模的生产工艺。(The invention discloses a kind of internal-thread seamless steel pipe internal model production technologies, comprising the following steps: 1) selection and sharp processing；2) Bononizing pretreatment；3) heat；4) it quenches；5) it is tempered；6) air-cooled.The invention belongs to steel pipe's production mold machining technology fields, and specifically there is provided a kind of improves die surface hardness height and wearability by Bononizing pretreatment to extend die life, heat-treatment quenching is cooperated to handle the production technology for improving die matrix intensity and toughness, carrying out the air-cooled internal-thread seamless steel pipe internal model for avoiding face crack and oxide layer from improving surface smoothness to mold using protective gas with high-strength material.)

1. a kind of internal-thread seamless steel pipe internal model production technology, special type are: the following steps are included:

Step 1:

Selection and sharp processing: selecting high-strength die material, carries out machining to mold materials, is processed into surface and has The die blank of groove；

Step 2:

Bononizing pretreatment: spreading one layer of boriding medium in roasting pot, die blank be put into boriding medium, then with boriding medium by mold hair Base is buried completely, and roasting pot is sealed, and roasting pot is put into heating furnace；

Step 3:

Heat treatment: being preheating to 400-500 DEG C for roasting pot, keep the temperature 120-240min, is then heated to 850~870 DEG C, heating Speed control keeps the temperature 120-360min in 10-20 DEG C/min；940~960 DEG C are then heated to, heating rate is controlled in 20- 30 DEG C/min, 30~90min is kept the temperature, heating speed is controlled in 20~30 DEG C/min；

Step 4:

Quenching: roasting pot is taken out from heating furnace, is taken out die blank from roasting pot with fixture, and be put into salt water and quench Fire is to room temperature；

Step 5:

Tempering: the mold for being quenched to room temperature being put into heating furnace and is heated to 630-650 DEG C, soaking time 60-120min；

Step 6:

It is air-cooled: the mold after tempering being placed in the cooler bin full of protective gas and is air-cooled to room temperature.

2. a kind of internal-thread seamless steel pipe internal model production technology according to claim 1, it is characterised in that: institute in step 1 State its component of high-strength die material and weight percent are as follows: C:0.36~0.38%；Si:0.30~0.50%；P≤ 0.035%；S≤0.010%；Cr:6.8~7.6%；Mo:4.7~5.4%；V:1.8~2.6%；Remaining is Fe.

3. a kind of internal-thread seamless steel pipe internal model production technology according to claim 1, it is characterised in that: institute in step 2 State boriding medium composition and percentage are as follows: borax 25%, sodium fluoborate 8%, clay 22%, urea 7%, ferrosilicon 6%, ammonium hydrogen carbonate 4%, azodicarbonamide 2%, calcium carbonate 0.25%, titanium dioxide 0.025%, rare earth fluoride 0.3%, remaining is the stone of 1:1 Ink and charcoal.

4. a kind of internal-thread seamless steel pipe internal model production technology according to claim 1, it is characterised in that: institute in step 4 State the sodium chloride solution that salt water is 8-12%.

5. a kind of internal-thread seamless steel pipe internal model production technology according to claim 1, it is characterised in that: institute in step 6 Stating protective gas is carbon dioxide or nitrogen.

Technical field

The invention belongs to steel pipe's production mold machining technology fields, in particular to a kind of internal-thread seamless steel pipe internal model to produce Technique.

Background technique

Internal-thread seamless steel pipe is a kind of special-shaped seamless steel pipe of the inner surface with spiral convex rib, is generally used for high-pressure boiler It is interior, due to the indent and convex internal screw thread of its inner wall, it can effectively overcome the laminar flow phenomenon generated when medium slow flow in steel pipe, together When can inhibit the steam blanket effect of steel pipe inner wall, improve the heat-transfer effect of boiler water wall, keep tube wall temperature more uniform.

The rough screw thread needs of internal-thread seamless steel pipe inner surface are formed in cold-drawn process, it is desirable that inner membrance when cold-drawn Surface has groove, and when cold-drawn, steel pipe is made the groove on inner membrance in the inner surface of steel pipe extrudes by the circumferential pressure of external mold Screw thread convex ribs, while Mandrel Rotating device drives internal model to rotate by plug, is formed in uniform, continuous on the inner wall of steel pipe Screw thread convex ribs.Internal model needs to bear in the process huge pressure, at the same the groove on surface because rotation will receive it is huge Shearing force, therefore the hardness of internal model, intensity and wearability requirement are very high.

Summary of the invention

To solve above-mentioned existing problem, the present invention provides a kind of surface hardness high-wearing features can prolong the service life by force, The internal-thread seamless steel pipe internal model production technology of the good flawless of the high flexible of basis material intensity, surface smoothness and oxide layer. The working surface of the internal-thread seamless steel pipe internal model manufactured using this method has very high hardness and wearability, matrix With enough intensity and toughness, the cold-drawn suitable for internal-thread seamless steel pipe is produced.

The technical solution adopted by the invention is as follows: a kind of internal-thread seamless steel pipe internal model production technology, comprising the following steps:

Step 1:

Selection and sharp processing: selecting high-strength die material, carries out machining to mold materials, is processed into surface With fluted die blank；

Step 2:

Bononizing pretreatment: spreading one layer of boriding medium in roasting pot, die blank be put into boriding medium, then with boriding medium by mould Tool blank is buried completely, and roasting pot is sealed, and roasting pot is put into heating furnace；

Step 3:

Heat treatment: being preheating to 400-500 DEG C for roasting pot, keep the temperature 120-240min, be then heated to 850~870 DEG C, Heating rate is controlled in 10-20 DEG C/min, and keeps the temperature 120-360min；940~960 DEG C are then heated to, heating rate control In 20-30 DEG C/min, 30~90min is kept the temperature, heating speed is controlled in 20~30 DEG C/min；

Step 4:

Quenching: roasting pot is taken out from heating furnace, is taken out die blank from roasting pot with fixture, and be put into salt water In be quenched to room temperature；

Step 5:

Tempering: the mold for being quenched to room temperature being put into heating furnace and is heated to 630-650 DEG C, soaking time 60-120min；

Step 6:

It is air-cooled: the mold after tempering being placed in the cooler bin full of protective gas and is air-cooled to room temperature；

Further, its component of high-strength die material described in step 1 and weight percent are as follows: C:0.36~ 0.38%；Si:0.30~0.50%；P≤0.035%；S≤0.010%；Cr:6.8~7.6%；Mo:4.7~5.4%；V: 1.8~2.6%；Remaining is Fe.

Further, the composition of boriding medium described in step 2 and percentage are as follows: borax 25%, sodium fluoborate 8%, clay 22%, urea 7%, ferrosilicon 6%, ammonium hydrogen carbonate 4%, azodicarbonamide 2%, calcium carbonate 0.25%, titanium dioxide 0.025%, Rare earth fluoride 0.3%, remaining is the graphite and charcoal of 1:1.

Further, salt water described in step 4 is the sodium chloride solution of 8-12%.

Further, protective gas described in step 6 is carbon dioxide or nitrogen.

Using the manufacturing technique method of process of the present invention production internal-thread seamless steel pipe internal model, have the following beneficial effects:

1, used high-strength die material, is capable of providing the intensity requirement of mold, and mold is enable to bear huge pressure And shearing force, while being a kind of molding material easy to process before heat treatment.

2, it joined Bononizing pretreatment during being heat-treated, it can be in 50-200 microns of high rigidity of die surface formation Boronation iron layer provides die surface wearability, effectively increases the service life of mold.

3, under the premise of Bononizing pretreatment is added, suitable heat treatment and quenching has been carried out to mold, improved mold base The intensity and toughness of body.

4, after being tempered it is air-cooled using with by the way of air exclusion, effectively prevent in general process air cooler air to mold Oxidation and crackle, greatly improve the bright and clean degree of die surface caused by surface.

Figure of description

Fig. 1 is a kind of internal-thread seamless steel pipe internal model production technological process of the present invention.

Specific embodiment

Invention is further described in detail combined with specific embodiments below.

A kind of internal-thread seamless steel pipe internal model production technology, specific steps are as follows:

High-strength die material is selected, machining is carried out to mold materials, is processed into the fluted mold of surface band Blank；One layer of boriding medium is spread in roasting pot, and die blank is put into boriding medium, is then covered die blank completely with boriding medium It buries, and roasting pot is sealed, roasting pot is put into heating furnace；Roasting pot is preheating to 400-500 DEG C, keeps the temperature 120- 240min is then heated to 850~870 DEG C, and heating rate is controlled in 10-20 DEG C/min, and keeps the temperature 120-360min；Then plus Heat is to 940~960 DEG C, and heating rate control keeps the temperature 30~90min in 20-30 DEG C/min, and heating speed is controlled 20~30 ℃/min；Roasting pot is taken out from heating furnace, is taken out die blank from roasting pot with fixture, and be put into salt quenching-in water To room temperature；The mold for being quenched to room temperature is put into heating furnace and is heated to 630-650 DEG C, soaking time 60-120min；It will tempering Mold afterwards is placed in the cooler bin full of protective gas and is air-cooled to room temperature.