Can a guy have temporary Nikah with girl if both willing just for sexual pleasure and then they divorce after few months (6-7 months)?
What if he do this with many girls different times.
This practice Halal and permissible?
A temporary marriage in Islam is called nikah al-Mut'a or al-Mut'ah نكاح المتعة and was a common practice in Jahiliyyah. Because Islam didn't invent any new kinds of marriage, but legalized some kind by giving it defined rulings and declared void others. Note متعة in Arabic means pleasure so this nikah in Jahilyah was performed for the pleasure of men and reduces women to sex objects.
The conditions for such a marriage are:
There's a difference of opinion among the different Muslim sects about it:
Here some of the sunni evidences and opinions:
Rabi' b. Sabra reported on the authority of his father that Allah's Apostle (ﷺ) prohibited the contracting of temporary marriage. (Sahih Muslim)
O people, I had permitted you to contract temporary marriage with women, but Allah has forbidden it (now) until the Day of Resurrection. So he who has any (woman with this type of marriage contract) he should let her off, and do not take back anything you have given to them (as dower). (Sahih Muslim)
Allah's Messenger (ﷺ) permitted temporary marriage for us. So I and another person went out and saw a woman of Bana 'Amir, who was like a young long-necked she-camel. We presented ourselves to her (for contracting temporary marriage), whereupon she said: What dower would you give me? I said: My cloak. And my companion also said: My cloak. And the cloak of-my companion was superior to my cloak, but I was younger than he. So when she looked at the cloak of my companion she liked it, and when she cast a glance at me I looked more attractive to her. She then said: Well, you and your cloak are sufficient for me. I remained with her for three nights, and then Allah's Messenger (ﷺ) said: He who has any such woman with whom he had contracted temporary marriage, he should let her off. (Sahih Muslim)
... The same scholar said regarding Al-Mut'a, "The marriage is invalid and its condition is illegal. … (Sahih al-Bukhari)
In the English Wikipedia Article -which seems more biased and show mainly pro-mut'ah statements- you may read an explanation of the quote referring to abu Hanifa from Sahih al-Bukhari:
The Hanafi school of Sunni jurisprudence argues that although the nikah mut'ah contract itself is valid, marriage is regarded as a permanent condition and therefore, the temporary element of the contract makes it void.
Note that sunni texts actually confirm that the ruling was changed several times: it was legal, then declared as illegal on the day of the battle of Khaybar (See for example here), then again made legal for the Ghazwa of Fath Mekka and finally declared as illegal at the third day of Fath (so it was declared legal again for three days: see for example in Sunan ibn Majah and Sahih Muslim).
Some references that allow it:
In the following I'm translating from Arabic , as the translation is mine take it with the necessary care!
عن أبي بصير قال: سألت أبا جعفر (عليه السلام) عن المتعة، فقال: نزلت في القرآن (فما استمتعتم به منهن فآتوهن أجورهن فريضة فلا جناح عليكم فيما تراضيتم به من بعد الفريضة . (In al-Kulayni's Al-Kafi الكافي Volume 5, Page 448 -see here- Hadith 1 /Chapters of Mut'a أبواب المتعة)
Abu Bassir said: I've asked abu Ja'afar (Peace be upon him) about Mut'a. And he answerd: it was revealed in the Qur'an: "So for whatever you enjoy [of marriage] from them, give them their due compensation as an obligation. And there is no blame upon you for what you mutually agree to beyond the obligation. (4:24)"
عن عمر بن أذينة، عن أبي عبد الله (عليه السلام) قال: قلت: كم تحل من المتعة؟ قال: فقال: هن بمنزلة الإماء
From 'Umar ibn Udhaynah from abu 'Abdillah (Peace be upon him) who said: I've asked how much (how many women are) is legal for Mut'a?. He said: He answered: They are similar to slave girls. (Al-Kafi Volume 5, Page 451 -see here- Hadith 1 /Chapter that they are similar to slave girls and not among the four (wives) انهن بمنزلة الإماء وليست من الأربع)
You may find further evidences and details in the same source pages 448ff.
I could find two among these narrations that quote a discussion between abu Hanifa and imam as-Sadiq. Actually a meeting between these two scholars is highly suspected by historians. Even if both early Hanafi's and Shi'a sources give this meeting a special status.
Shi'a sources set a special emphasis on the fact that 'Umar ibn al-Khattab was the one who finally prohibited it (see for example the 2nd hadith in the first link from al-Kafi and the 4th hadith here) the hadith from Sunan ibn Majah shows that 'Umar seemed to be very certain that this practice was declared void in a big gathering of sahabah otherwise he wouldn't ask for forty witnesses saying otherwise for anybody who wanted to commit it.
Some references that prohibit it:
عن علي (عليهم السلام) قال: حرم رسول الله (صلى الله عليه وآله) يوم خيبر لحوم الحمر الأهلية ونكاح المتعة.
'Ali (Peace be upon him) said: Allah's Apostle (Allahs Blessings be upon him and His family) on the Day of Khaibar prohibited for ever the contracting of temporary marriage and eating of the flesh of the domestic asses. (Wassail a-Shi'a of Volume 21 page 12 Hadith 32 (26387) here of Al-Hurr al-Amili and Tahdeeb al-Ahakam of at-Tusi Hadith 10 (1085) here)
عن الرضا (عليه السلام) - في حديث - قال: لا ينبغي لك أن تتزوج إلا (بمأمونة) ان الله عز وجل يقول: ﴿الزاني لا ينكح إلا زانية أو مشركة والزانية لا ينكحها إلا زان أو مشرك وحرم ذلك على المؤمنين﴾
From ar-Rida (Peace be upon him) -in a hadith- who said:You should not marry but a faithful (woman) Alllah the Almighty says: "The fornicator does not marry except a [female] fornicator or polytheist, and none marries her except a fornicator or a polytheist, and that has been made unlawful to the believers." (24:3) (Wassail a-Shi'a Volume 21 page 24 Hadith 3 (26428) here)
عن عبد الله بن سنان قال: سألت أبا عبد الله عليه السلام عن المتعة فقال: لا تدنس نفسك بها
From 'Abdullah ibn Sinan who said: I asked abu 'Abdillah (peace be upon him) about Mut'a and he answered: don't besmear yourself with it. (Bihar al-Anwar of al-Majalisi Volume 100 page 318 Hadith 34 here )
عن هشام بن الحكم، عن أبي عبد الله عليه السلام قال: ما تفعلها عندنا إلا الفواجر
From Hisahm ibn Hakam from abu 'Abdillah peace be upon him who said (Concerning Mut'a): only the adulteress among us commit it. (Bihar al-Anwar Volume 100 page 318 Hadith 36 here -same page as the hadith above)
Imam as-Sadiq was also quoted to have forbidden it (declared it haram) to some of his visitors (some explain this by taqiyyah) and in other quotes he was asked about the women of his household by 'Abdullah ibn 'Umayr and he got angry at him and refrained from his statement (about declaring it legal).
For further information refer to my answer on Is sex by couples married under nikah mut'ah interpreted as zina in Sunni Islam, and punishable under Sharia?
See also in Arabic Wikipedia Article here.
Yes, temporary nikah is permissible even if it is only to fulfill ones sexual needs. The temporary marriage ceases at the end of the agreed time, which should be decided before the marriage, or the man can divorce her before that the time if wishes.
Yes, it is also permissible to engage in temporary nikah with multiple woman at the same time. Not sure if it can be more than 4 or not at the same time.