Steypa í blokk

Fyrir allt sem fram fer í skúrnum eða eftir atvikum, úti á stétt.

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gustiflyg
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Steypa í blokk

Postfrá gustiflyg » 29.apr 2016, 12:44

Sælir félagar, mig langar að forvitnast hvort einhver hérna hafi einhverja reynslu af því að steypa í sprungur í vélarblokk og þá hvaða efni hafa verið notuð?.
Ég er búinn að prófa JP.Weld og það virðist ekki vera að virka nógu vel. Öll ráð vel þeginn.

Kv. Ágúst




villi58
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Re: Steypa í blokk

Postfrá villi58 » 29.apr 2016, 15:59

Menn suðu í blokkir með pinna ef þetta er steypujárn, tókst að vísu misjafnlega, gott að fá leiðbeiningar frá einum gömlum vönum í svona.

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snöfli
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Re: Steypa í blokk

Postfrá snöfli » 29.apr 2016, 17:23

http://www.lincolnelectric.com/en-us/su ... etail.aspx

Þetta var og er gert. Hér er ein leiðbeining:

Cast iron is difficult, but not impossible, to weld. In most cases, welding on cast iron involves repairs to castings, not joining casting to other members. The repairs may be made in the foundry where the castings are produced, or may be made to repair casting defects that are discovered after the part is machined. Mis-machined cast iron parts may require repair welding, such as when holes are drilled in the wrong location. Frequently, broken cast iron parts are repaired by welding. Broken cast iron parts are not unusual, given the brittle nature of most cast iron.
While there are a variety of types of cast iron, the most common is gray cast iron, and these guidelines are directed toward this type of material.

A few facts about cast iron help in understanding the welding challenges. Cast iron typically has a carbon content of 2% - 4%, roughly 10 times as much as most steels. The high carbon content causes the carbon to form flakes of graphite. This graphite gives gray cast iron its characteristic appearance when fractured.

When castings are made, molten iron is poured into a mold and allowed to slowly cool. When this high carbon material is allowed to cool slowly, crack free castings can be made. Remembering this is helpful when welding cast iron: during and after welding, the casting must either be allowed to cool slowly, or should be kept cool enough that the rate of cooling is not important.

A critical temperature in most cast iron is about 1450 degrees F. When at this temperature, conditions that can lead to cracking occur. While the arc will heat the casting to temperatures above this level, it is important that the casting not be held at this temperature for long periods of time.

Electrode Selection
If the part is to be machined after welding, a nickel-type electrode will be required. Use Lincoln Softweld® 99Ni stick electrode for single pass, high dilution welds. Softweld 55 Ni is preferred for multiple pass welds. Sometimes, root passes are put in with Softweld 99 Ni, followed by fill passes with Softweld 55 Ni. For welds where machining is not required, and where the weld is expected to rust like the cast iron, Lincoln Ferroweld® stick electrode can be used.

To Heat, or not to Heat
In general, it is preferred to weld cast iron with preheat--and lots of it. But, another way to successfully weld cast iron is to keep it cool--not cold, but cool. Below, both methods will be described. However, once you select a method, stick with it. Keep it hot, or keep it cool, but don't change horses in the middle of the stream.

Welding Techniques with Preheat
Preheating the cast iron part before welding will slow the cooling rate of the weld, and the region surround the weld. It is always preferred to heat the entire casting, if possible. Typical preheat temperatures are 500-1200 degrees F. Don’t heat over 1400 degrees F since that will put the material into the critical temperature range. Preheat the part slowly and uniformly.

Weld using a low current, to minimize admixture, and residual stresses. In some cases, it may be necessary to restrict the welds to small, approximately 1-inch long segments to prevent the build up of residual stresses that can lead to cracking. Peening of weld beads can be helpful in this regard as well.

After welding, allow the part to slowly cool. Wrapping the casting in an insulating blanket, or burying it in dry sand, will help slow cooling rates, and reduce cracking tendencies.

Welding Techniques without Preheat
The size of the casting, or other circumstances, may require that the repair be made without preheat. When this is the case, the part needs to be kept cool, but not cold.

Raising the casting temperature to 100 degrees F is helpful. If the part is on an engine, it may be possible to run it for a few minutes to obtain this temperature. Never heat the casting so hot that you cannot place your bare hand on it.

Make short, approximately 1” long welds. Peening after welding is important with this technique. Allow the weld and the casting to cool. Do not accelerate the rate of cooling with water or compressed air. It may be possible to weld in another area of the casting while the previous weld cools. All craters should be filled. Whenever possible, the beads should be deposited in the same direction, and it is preferred that the ends of parallel beads not line up with each other.

Sealing Cracks
Because of the nature of cast iron, tiny cracks tend to appear next to the weld even when good procedures are followed. If the casting must be water tight, this can be a problem. However, leaking can usually be eliminated with some sort of sealing compound or they may rust shut very soon after being returned to service.

The Studding Method
One method used to repair major breaks in large castings is to drill and tap holes over the surfaces that have been beveled to receive the repair weld metal. Screw steel studs into the threaded holes, leaving 3/16” (5 mm) to ¼” (6 mm)of the stud above the surface. Using the methods discussed above, weld the studs in place and cover the entire surface of the break with weld deposit. Once a good weld deposit is made, the two sides of the crack can be welded together.

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snöfli
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Re: Steypa í blokk

Postfrá snöfli » 29.apr 2016, 17:39

Járnsteypa (pottur) tekur vel upp þýstingsálag er verr tog. Viðgerðin mun taka en ver upp togálag en áður því gæti þurft að styrkja eða spengja hlutinn, ef hluturinn brotnaði út af togálagi til að byrja með.

l.

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jongi
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Re: Steypa í blokk

Postfrá jongi » 29.apr 2016, 20:42

Tig sjóða með stimpil hring sem fillir hefur virkað
gott að eiga gamla netta stimpilhringi í skúffu ef sjóða þarf blokk eða annan pott


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gustiflyg
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Re: Steypa í blokk

Postfrá gustiflyg » 29.apr 2016, 22:06

Gleymdi víst að skrifa að það er búið að reyna að sjóða í blokkina með einhverjum spes vír en það gekk víst ekki betur en það að það grætur með suðunni á nokkrum stöðum. Langaði að prófa að steypa yfir það og sjá hvort það myndi halda.


Heddportun
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Re: Steypa í blokk

Postfrá Heddportun » 29.apr 2016, 22:34

Til að gera við cast þarf að hita alla blokkina upp vel og sjóða með logsuðu og nickel vír svo það haldi og geti teygst aðeins

Þú þarft að banka í suðuna og blokkin þarf að kólnq hægt og jafnt niður t.d með steinull

Best er að sauma í sprungur með tappa setti,þá er ekkert vesen með að hita ogþær springi en stundum er orðið of þunnt í til að gera við ef þetta er í vatnsgang


sra
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Re: Steypa í blokk

Postfrá sra » 29.apr 2016, 22:47

Gömul ráð reynast oft best. Ca 3-5 mm þykk koparbót klöppuð að sprungu eða gati og síðan borað og snittað í blokk, nokkuð þétt ( 10-15 mm milli gata)
ca 4-5 mm skrúfur, gúmípakkning undir og málið dautt.
Gangi þér vel


olei
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Re: Steypa í blokk

Postfrá olei » 29.apr 2016, 23:45

Hvað lekur, kælivatn eða olía?


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gustiflyg
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Re: Steypa í blokk

Postfrá gustiflyg » 30.apr 2016, 12:23

Það lekur kælivatn

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jeepcj7
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Re: Steypa í blokk

Postfrá jeepcj7 » 30.apr 2016, 12:40

Hvernig blokk er um að ræða?
Heilagur Henry rúlar öllu.


grimur
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Re: Steypa í blokk

Postfrá grimur » 01.maí 2016, 01:12

Wondarweld blokkarþéttiefni frá Holts hefur virkað hjá mér, tókst meiraðsegja að stöðva þrýstileka í heddi inná vatnsgang með þessu stöffi. Fylgja leiðbeiningum alveg í hörgul og þetta gæti virkað.
Þennan venjulega músaskíts vatnskassaþétti hef ég aldrei fengið til að gera nokkurn skapaðan hlut að gagni.

Kv
Grímur


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gustiflyg
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Re: Steypa í blokk

Postfrá gustiflyg » 01.maí 2016, 12:29

5,9 cummins blokk


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