Re: [MW:25918] PWHT Cycle Of P335-P5B (P9)

You have to allow martensite to formally and at the same time avoid cold cracking. Therefor keep the 200 degC for 2 hours and then proceed as you propose

Sent from my Samsung Galaxy smartphone.

-------- Original message --------

From: 'Mostafa Kamel Hussein' via Materials & Welding <materials-welding@googlegroups.com>

Date: 17/01/2017 11:40 (GMT+02:00)

To: Materials-welding <materials-welding@googlegroups.com>

Subject: [MW:25910] PWHT Cycle Of P335-P5B (P9)

Dear Sir

Really now we are in critical situation regarding PWHT of A335 - P5B (Grade P9). The cycle in brief as attached. first preheat at 200°C then cooling to ambient temperature (20-80°C) for minimum 30 minutes as holding time. after that PWHT cycle starts by heating rate of maximum 100°C /hr till reaching to soaking temperature (704-760°C) for 2hrs. finally, cooling rate of maximum 100°C /hr.

My question is: it this PWHT cycle for P335-P9 true specially cooling to ambient temperature (20-80°C) as i know it's may cause delay crack?

and if this cycle wrong, can you provide me with the correct one which i can built PQR on it?

Your quick reply is highly appreciated.

Regards,

Mostafa K

Comments

Heat tint (temper) colours on stainless steel surfaces heated in air // Heat tint

Introduction The colour formed when stainless steel is heated, either in a furnace application or in the heat affected zone of welds, is dependent on several factors that are related to the oxidation resistance of the steel. The heat tint or temper colour formed is caused by the progressive thickening of the surface oxide layer and so, as temperature is increased, the colours change. Oxidation resistance of stainless steels However, there are several factors that affect the degree of colour change and so there is no a single table of colour and temperature that represents all cases. The colours formed can only be used as an indication of the temperature to which the steel has been heated. Factors affecting the heat tint colours formed Steel composition The chromium content is the most important single factor affecting oxidation resistance. The higher the chromium, the more heat resistant the steel and so the development of the heat tint colou...

Materails FAQs

Q: What are equivalents for standard Q 235 B (and Q 235 A) for U-channels? (asked by: boris.vielhaber@vait.com) A: DIN Nr. = 2393 T.2, 2394 T.2, EN 10025 W. Nr. DIN 17007 = 1.0038 Design DIN 17006 = RSt 37-2, S235JRG2 (Fe 360 B) Q: What is St DIN 2391 BK material? (asked by: dmcandrews@automaticstamp.com) A: Precision steel tubes, cold-finished/hard. Q: What is C.D.W. Boiler Tube? (asked by: montydude123@yahoo.com) A: Cold Drawn Welded Boiler Tube. Q: WHAT IS W.Nr. 1.4301? PLS TELL US IN EASY LANGUAGUE (asked...

The Schaeffler and Delong diagrams for predicting ferrite levels in austenitic stainless steel welds

Introduction Ferrite is important in avoiding hot cracking in during cooling from welding of austenitic stainless steels. 'Constitution diagrams' are used to predict ferrite levels from the composition by comparing the effects of austenite and ferrite stabilising elements. The Schaeffler and Delong diagrams are the original methods of predicting the phase balances in austenitic stainless steel welds. Nickel and chromium equivalents A 'nickel equivalent' is calculated for the austenite stabilising elements and a 'chromium equivalent' ferrite stabilising elements. These are used as the axes for the diagrams, which show the compositional equivalent areas where the phases austenite, ferrite, martensite (and mixtures of these) should be present. Although intended to show the phase balance of weld fillers, these diagrams can also be used to illustrate the phase balance of the 'parent' material. There are different diagrams for dif...

Materials & Welding

Search This Blog